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Ziemnicki DM, McDonald KA, Molitor SL, Egolf JB, Cruz JP, Lee KE, Zelik KE. Development and Preliminary Evaluation of a Bimodal Foot Prosthesis for Walking and Running. J Biomech Eng 2024; 146:091010. [PMID: 38758531 DOI: 10.1115/1.4065516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Accepted: 04/29/2024] [Indexed: 05/18/2024]
Abstract
People often alternate between bouts of walking and running, for instance, when adults participate in recreational activities. Transitioning between activities can be challenging for prosthesis users because existing prosthetic feet are not well-suited for both tasks. Meanwhile, switching between prostheses for different tasks is often impractical. Collectively, these challenges can present barriers to physical activity participation for people with limb loss, which can negatively impact social or physical health. This work describes the development and evaluation of a passive bimodal prosthetic foot prototype with different configurations and stiffnesses for walking and running. Users rated the bimodal prosthesis higher for standing and walking compared to a running prosthesis (+2.3 for both tasks on a seven-point Likert scale). Users rated the bimodal prosthesis higher for running compared to a walking prosthesis (+1.7 and +0.5 for 2.0 and 2.5 m/s running, respectively). Changing from walking to running mode increased the device's stiffness by 23-84%, depending on the user's preference. Users could switch between bimodal prosthesis walking and running modes quickly (21.3 ± 12.0 s). Overall, the preliminary results were encouraging in terms of user satisfaction, stiffness change between modes, and mode-switching speed. These findings motivate future exploration of this bimodal prosthesis concept.
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Affiliation(s)
- David M Ziemnicki
- Department of Mechanical Engineering, Vanderbilt University, 2201 West End Avenue, Nashville, TN 37235
| | - Kirsty A McDonald
- School of Health Sciences, University of New South Wales, Level 2, Wallace Wurth Building, Sydney 2052, NSW, Australia
| | - Stephanie L Molitor
- Department of Biomedical Engineering, Vanderbilt University, 2201 West End Avenue, Nashville, TN 37235; Walker Department of Mechanical Engineering, The University of Texas at Austin, 204 E. Dean Keeton Street, Austin, TX 78712
| | - Jeremiah B Egolf
- Department of Biomedical Engineering, Vanderbilt University, 2201 West End Avenue, Nashville, TN 37235
| | - Justin P Cruz
- Department of Biomedical Engineering, Vanderbilt University, 2201 West End Avenue, Nashville, TN 37235; Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave, Ward Building 1-003, Chicago, IL 60611-3008
| | - Kathryn E Lee
- Department of Biomedical Engineering, Vanderbilt University, 2201 West End Avenue, Nashville, TN 37235
| | - Karl E Zelik
- Department of Mechanical Engineering, Vanderbilt University, 2201 West End Avenue, Nashville, TN 37235; Department of Biomedical Engineering, Vanderbilt University, 2201 West End Avenue, Nashville, TN 37235; Department of Physical Medicine and Rehabilitation, Vanderbilt University, 2201 West End Avenue, Nashville, TN 37235
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Rogers-Bradley E, Yeon SH, Landis C, Lee DRC, Herr HM. Variable-stiffness prosthesis improves biomechanics of walking across speeds compared to a passive device. Sci Rep 2024; 14:16521. [PMID: 39019986 PMCID: PMC11255255 DOI: 10.1038/s41598-024-67230-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Accepted: 07/09/2024] [Indexed: 07/19/2024] Open
Abstract
Ankle push-off power plays an important role in healthy walking, contributing to center-of-mass acceleration, swing leg dynamics, and accounting for 45% of total leg power. The majority of existing passive energy storage and return prostheses for people with below-knee (transtibial) amputation are stiffer than the biological ankle, particularly at slower walking speeds. Additionally, passive devices provide insufficient levels of energy return and push-off power, negatively impacting biomechanics of gait. Here, we present a clinical study evaluating the kinematics and kinetics of walking with a microprocessor-controlled, variable-stiffness ankle-foot prosthesis (945 g) compared to a standard low-mass passive prosthesis (Ottobock Taleo, 463 g) with 7 study participants having unilateral transtibial amputation. By modulating prosthesis stiffness under computer control across walking speeds, we demonstrate that there exists a stiffness that increases prosthetic-side energy return, peak power, and center-of-mass push-off work, and decreases contralateral limb peak ground reaction force compared to the standard passive prosthesis across all evaluated walking speeds. We demonstrate a significant increase in center-of-mass push-off work of 26.1%, 26.2%, 29.6% and 29.9% at 0.75 m/s, 1.0 m/s, 1.25 m/s, and 1.5 m/s, respectively, and a significant decrease in contralateral limb ground reaction force of 3.1%, 3.9%, and 3.2% at 1.0 m/s, 1.25 m/s, and 1.5 m/s, respectively. This study demonstrates the potential for a quasi-passive microprocessor-controlled variable-stiffness prosthesis to increase push-off power and energy return during gait at a range of walking speeds compared to a passive device of a fixed stiffness.
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Affiliation(s)
- Emily Rogers-Bradley
- K. Lisa Yang Center for Bionics, Massachusetts Institute of Technology, Cambridge, 02139, USA
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, 02139, USA
- Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, T2N 1N4, Canada
| | - Seong Ho Yeon
- K. Lisa Yang Center for Bionics, Massachusetts Institute of Technology, Cambridge, 02139, USA
- Media Lab, Massachusetts Institute of Technology, Cambridge, 02142, USA
| | - Christian Landis
- K. Lisa Yang Center for Bionics, Massachusetts Institute of Technology, Cambridge, 02139, USA
- Media Lab, Massachusetts Institute of Technology, Cambridge, 02142, USA
| | - Duncan R C Lee
- K. Lisa Yang Center for Bionics, Massachusetts Institute of Technology, Cambridge, 02139, USA
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, 02139, USA
| | - Hugh M Herr
- K. Lisa Yang Center for Bionics, Massachusetts Institute of Technology, Cambridge, 02139, USA.
- Media Lab, Massachusetts Institute of Technology, Cambridge, 02142, USA.
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Mueller E, Major MJ. The effects of slope-adaptive prosthetic feet on sloped gait performance and quality in unilateral transtibial prosthesis users: A scoping review. JOURNAL OF PROSTHETICS AND ORTHOTICS : JPO 2024; 36:e49-359. [PMID: 39055064 PMCID: PMC11271739 DOI: 10.1097/jpo.0000000000000501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
Introduction In non-impaired human locomotion, sagittal-plane slope adaptation of the foot-ankle complex is a volitional function driven by neuromotor control to support upright posture and forward ambulation. Loss of this adaptation due to transtibial amputation can lead to instability and compensatory motions as most commercially-available prosthetic feet do not permit automatic slope adjustments. A selection of slope-adaptive feet (SAF) have been developed to promote biomimetic ankle motion while ambulating over slopes. This review evaluated the current literature to assess the effects of SAF prostheses on sloped gait performance in unilateral transtibial prosthesis users. Methods Four databases (PubMed, Embase, CINAHL, IEEE Xplore) were searched on April 28, 2022, for relevant articles. Search keywords covered the general terms "transtibial," "amputation," "slope," "adaptive," and "gait", and included articles comparing a SAF prosthesis to a non-SAF prosthesis condition. Data were extracted for analysis and results were grouped according to outcomes to identify trends and aid interpretation of slope adaptation effects on gait. Results Of the 672 articles screened, 24 met the selection criteria and were included in this review, published between 2009 and 2022. The non-SAF condition included dynamic response feet and SAF prostheses with the adaptability function inactive. Outcomes included biomechanical variables (joint dynamics, gait symmetry, toe clearance), clinical outcome measures, and energy expenditure. All SAF demonstrated some form of foot-ankle slope gradient adaptability, but effects on other joint dynamics were inconsistent. Minimum toe clearance during incline and decline walking was greater when using SAF compared to non-SAF in all reporting studies. Conclusions Results generally suggest improvements in gait quality, comfort, and safety with use of SAF compared to non-SAF during slope walking. However, variations in tested SAF and walking gradients across studies highlight the need for research to elucidate walking condition effects and advantages of specific designs. Clinical Relevance Slope-adaptive prosthetic feet may improve user gait quality and comfort and enhance gait safety by increasing minimum toe clearance. Patients who encounter slopes regularly should be considered as potential users of SAF if indicated appropriately.
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Affiliation(s)
- Emily Mueller
- Northwestern University Department of Physical Medicine and Rehabilitation, Chicago, IL, USA
| | - Matthew J Major
- Northwestern University Department of Physical Medicine and Rehabilitation, Chicago, IL, USA
- Northwestern University Department of Biomedical Engineering, Evanston, IL, USA
- Jesse Brown VA Medical Center, Chicago, IL, USA
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Teater RH, Zelik KE, McDonald KA. Biomechanical effects of adding an articulating toe joint to a passive foot prosthesis for incline and decline walking. PLoS One 2024; 19:e0295465. [PMID: 38758923 PMCID: PMC11101096 DOI: 10.1371/journal.pone.0295465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 04/23/2024] [Indexed: 05/19/2024] Open
Abstract
Walking on sloped surfaces is challenging for many lower limb prosthesis users, in part due to the limited ankle range of motion provided by typical prosthetic ankle-foot devices. Adding a toe joint could potentially benefit users by providing an additional degree of flexibility to adapt to sloped surfaces, but this remains untested. The objective of this study was to characterize the effect of a prosthesis with an articulating toe joint on the preferences and gait biomechanics of individuals with unilateral below-knee limb loss walking on slopes. Nine active prosthesis users walked on an instrumented treadmill at a +5° incline and -5° decline while wearing an experimental foot prosthesis in two configurations: a Flexible toe joint and a Locked-out toe joint. Three participants preferred the Flexible toe joint over the Locked-out toe joint for incline and decline walking. Eight of nine participants went on to participate in a biomechanical data collection. The Flexible toe joint decreased prosthesis Push-off work by 2 Joules during both incline (p = 0.008; g = -0.63) and decline (p = 0.008; g = -0.65) walking. During incline walking, prosthetic limb knee flexion at toe-off was 3° greater in the Flexible configuration compared to the Locked (p = 0.008; g = 0.42). Overall, these results indicate that adding a toe joint to a passive foot prosthesis has relatively small effects on joint kinematics and kinetics during sloped walking. This study is part of a larger body of work that also assessed the impact of a prosthetic toe joint for level and uneven terrain walking and stair ascent/descent. Collectively, toe joints do not appear to substantially or consistently alter lower limb mechanics for active unilateral below-knee prosthesis users. Our findings also demonstrate that user preference for passive prosthetic technology may be both subject-specific and task-specific. Future work could investigate the inter-individual preferences and potential benefits of a prosthetic toe joint for lower-mobility individuals.
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Affiliation(s)
- Rachel H. Teater
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, United States of America
| | - Karl E. Zelik
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, United States of America
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States of America
- Department of Physical Medicine and Rehabilitation, Vanderbilt University, Nashville, TN, United States of America
| | - Kirsty A. McDonald
- School of Health Sciences, University of New South Wales, Sydney, NSW, Australia
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Klute GK, Mulcahy CW. Sagittal and transverse ankle angle coupling can influence prosthetic socket transverse plane moments. FRONTIERS IN REHABILITATION SCIENCES 2024; 5:1354144. [PMID: 38638287 PMCID: PMC11024427 DOI: 10.3389/fresc.2024.1354144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 03/05/2024] [Indexed: 04/20/2024]
Abstract
Introduction The intact foot and ankle comprise a complex set of joints that allow rotation in multiple planes of motion. Some of these motions are coupled, meaning rotation in one plane induces motion in another. One such coupling is between the sagittal and transverse planes. For every step, plantar- and dorsi-flexion motion is coupled with external and internal rotation of the shank relative to the foot, respectively. There is no prosthetic foot available for prescription that mimics this natural coupling. The purpose of this study was to determine if a sagittal:transverse ankle angle coupling ratio exists that minimizes the peak transverse plane moment during prosthetic limb stance. Methods A novel, torsionally active prosthesis (TAP) was used to couple sagittal and transverse plane motions using a 60-watt motor. An embedded controller generated transverse plane rotation trajectories proportional to sagittal plane ankle angles corresponding to sagittal:transverse coupling ratios of 1:0 (rigid coupling analogous to the standard-of-care), 6:1, 4:1, 3:1, and 2:1. Individuals with unilateral transtibial amputation were block randomized to walk in a straight line and in both directions around a 2 m circle at their self-selected speed with the TAP set at randomized coupling ratios. The primary outcome was the peak transverse plane moment, normalized to body mass, during prosthetic limb stance. Secondary outcomes included gait biomechanic metrics and a measure of satisfaction. Results Eleven individuals with unilateral transtibial amputations participated in the study. The 6:1 coupling ratio resulted in reduced peak transverse plane moments in pairwise comparisons with 3:1 and 2:1 coupling ratios while walking in a straight line and with the prosthesis on the outside of the circle (p < .05). Coupling ratio had no effect on gait biomechanic metrics or satisfaction. Discussion The general pattern of results suggests a quadratic relationship between the peak transverse plane moment and coupling ratio with a minimum at the 6:1 coupling ratio. The coupling ratio did not appear to adversely affect propulsion or body support. Subjects indicated they found all coupling ratios to be comfortable. While a mechatronic prosthesis like the TAP may have limited commercial potential, our future work includes testing a robust, passive prosthetic foot with a fixed coupling ratio.
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Affiliation(s)
- Glenn K. Klute
- US Department of Veterans Affairs, Centerfor Limb Loss and MoBility, Seattle, WA, United States
- Department of Mechanical Engineering, University of Washington, Seattle, WA, United States
| | - Connor W. Mulcahy
- US Department of Veterans Affairs, Centerfor Limb Loss and MoBility, Seattle, WA, United States
- Department of Mechanical Engineering, University of Washington, Seattle, WA, United States
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Wager JC, Challis JH. Mechanics of the foot and ankle joints during running using a multi-segment foot model compared with a single-segment model. PLoS One 2024; 19:e0294691. [PMID: 38349945 PMCID: PMC10863889 DOI: 10.1371/journal.pone.0294691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 11/07/2023] [Indexed: 02/15/2024] Open
Abstract
The primary purpose of this study was to compare the ankle joint mechanics, during the stance phase of running, computed with a multi-segment foot model (MULTI; three segments) with a traditional single segment foot model (SINGLE). Traditional ankle joint models define all bones between the ankle and metatarsophalangeal joints as a single rigid segment (SINGLE). However, this contrasts with the more complex structure and mobility of the human foot, recent studies of walking using more multiple-segment models of the human foot have highlighted the errors arising in ankle kinematics and kinetics by using an oversimplified model of the foot. This study sought to compare whether ankle joint kinematics and kinetics during running are similar when using a single segment foot model (SINGLE) and a multi-segment foot model (MULTI). Seven participants ran at 3.1 m/s while the positions of markers on the shank and foot were tracked and ground reaction forces were measured. Ankle joint kinematics, resultant joint moments, joint work, and instantaneous joint power were determined using both the SINGLE and MULTI models. Differences between the two models across the entire stance phase were tested using statistical parametric mapping. During the stance phase, MULTI produced ankle joint angles that were typically closer to neutral and angular velocities that were reduced compared with SINGLE. Instantaneous joint power (p<0.001) and joint work (p<0.001) during late stance were also reduced in MULTI compared with SINGLE demonstrating the importance of foot model topology in analyses of the ankle joint during running. This study has highlighted that considering the foot as a rigid segment from ankle to MTP joint produces poor estimates of the ankle joint kinematics and kinetics, which has important implications for understanding the role of the ankle joint in running.
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Affiliation(s)
- Justin C. Wager
- Department of Physical Therapy and Human Movement Science, Sacred Heart University, Fairfield, Connecticut, United States of America
| | - John H. Challis
- Biomechanics Laboratory, Pennsylvania State University, University Park, Pennsylvania, United States of America
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7
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Herrin KR, Kwak ST, Rock CG, Chang YH. Gait quality in prosthesis users is reflected by force-based metrics when learning to walk on a new research-grade powered prosthesis. FRONTIERS IN REHABILITATION SCIENCES 2024; 5:1339856. [PMID: 38370855 PMCID: PMC10869520 DOI: 10.3389/fresc.2024.1339856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 01/12/2024] [Indexed: 02/20/2024]
Abstract
Introduction Powered prosthetic feet require customized tuning to ensure comfort and long-term success for the user, but tuning in both clinical and research settings is subjective, time intensive, and the standard for tuning can vary depending on the patient's and the prosthetist's experience levels. Methods Therefore, we studied eight different metrics of gait quality associated with use of a research-grade powered prosthetic foot in seven individuals with transtibial amputation during treadmill walking. We compared clinically tuned and untuned conditions with the goal of identifying performance-based metrics capable of distinguishing between good (as determined by a clinician) from poor gait quality. Results Differences between the tuned and untuned conditions were reflected in ankle power, both the vertical and anterior-posterior impulse symmetry indices, limb-force alignment, and positive ankle work, with improvements seen in all metrics during use of the tuned prosthesis. Discussion Notably, all of these metrics relate to the timing of force generation during walking which is information not directly accessible to a prosthetist during a typical tuning process. This work indicates that relevant, real-time biomechanical data provided to the prosthetist through the future provision of wearable sensors may enhance and improve future clinical tuning procedures associated with powered prostheses as well as their long-term outcomes.
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Affiliation(s)
- Kinsey R. Herrin
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, United States
- Institute for Robotics and Intelligent Machines, Georgia Institute of Technology, Atlanta, GA, United States
| | - Samuel T. Kwak
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, United States
| | - Chase G. Rock
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, United States
| | - Young-Hui Chang
- Institute for Robotics and Intelligent Machines, Georgia Institute of Technology, Atlanta, GA, United States
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, United States
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8
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Ármannsdóttir AL, Lecomte C, Lemaire E, Brynjólfsson S, Briem K. Perceptions and biomechanical effects of varying prosthetic ankle stiffness during uphill walking: A case series. Gait Posture 2024; 108:354-360. [PMID: 38227995 DOI: 10.1016/j.gaitpost.2024.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 12/28/2023] [Accepted: 01/02/2024] [Indexed: 01/18/2024]
Abstract
BACKGROUND Prosthetic foot stiffness, which is typically invariable for commercially available prosthetic feet, needs to be considered when prescribing a prosthetic foot. While a biological foot adapts its function according to the movement task, an individual with lower limb amputation may be limited during more functionally demanding gait tasks by their conventional energy storing and return prosthetic foot. RESEARCH QUESTION How do changes in prosthetic foot stiffness during incline walking affect biomechanical measures as well as perception of participants. METHODS Kinetic and kinematic data were collected during incline walking, for five participants with trans-tibial amputation. A mixed model analysis of variance was used to analyse the effects of changing the stiffness during incline walking, using a novel variable-stiffness unit built on a commercially available prosthetic foot. Biomechanical results were also analysed on an individual level alongside the participant feedback, for a better understanding of the various strategies and perceptions exhibited during incline walking. RESULTS Statistically significant effects were only observed on the biomechanical parameters directly related to prosthetic ankle kinematics and kinetics (i.e., peak prosthetic ankle dorsiflexion, peak prosthetic ankle power, dynamic joint stiffness during controlled dorsiflexion). Participant perception during walking was affected by changes in stiffness. Individual analyses revealed varied perceptions and varied biomechanical responses among participants. SIGNIFICANCE While changes in prosthesis mechanical properties influenced the amputee's experience, minimal immediate effects were found with the overall gait pattern. The reported inter-participant variability may be due to the person's physical characteristics or habitual gait pattern, which may influence prosthesis function. The ability to vary prosthetic foot stiffness during the assessment phase of setting up a prosthesis could provide useful information to guide selection of the appropriate prosthetic device for acceptable performance across a range of activities.
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Affiliation(s)
- Anna Lára Ármannsdóttir
- Research Centre of Movement Science, University of Iceland, Reykjavík, Iceland; Össur hf., Grjótháls 5, 110 Reykjavik, Iceland.
| | - Christophe Lecomte
- Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, School of Engineering and Natural Sciences, University of Iceland, Reykjavík, Iceland; Össur hf., Grjótháls 5, 110 Reykjavik, Iceland
| | - Edward Lemaire
- Faculty of Medicine, University of Ottawa, Ottawa, Canada
| | - Sigurður Brynjólfsson
- Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, School of Engineering and Natural Sciences, University of Iceland, Reykjavík, Iceland
| | - Kristín Briem
- Research Centre of Movement Science, University of Iceland, Reykjavík, Iceland
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Matijevich ES, Honert EC, Yang F, Lam WK, Nigg BM. Greater foot and footwear mechanical work associated with less ankle joint work during running. Sports Biomech 2024:1-19. [PMID: 38164950 DOI: 10.1080/14763141.2023.2296916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 11/23/2023] [Indexed: 01/03/2024]
Abstract
Footwear energy storage and return is often suggested as one explanation for metabolic energy savings when running in Advanced Athletic Footwear. However, there is no common understanding of how footwear energy storage and return facilitates changes in muscle and joint kinetics. The purpose of this study was to evaluate the magnitude and timing of foot, footwear and lower limb joint powers and work while running in Advanced and Traditional Athletic Footwear. Fifteen runners participated in an overground motion analysis study. Since footwear kinetics are methodologically challenging to quantify, we leveraged distal rearfoot power analyses ('foot + footwear' power) and evaluated changes in the magnitude and timing of foot + footwear power and lower limb joint powers. Running in Advanced Footwear resulted in greater foot + footwear work, compared to Traditional Shoes, and lower positive ankle work, potentially reducing the muscular demand on the runner. The timing of foot + footwear power varied only slightly across footwear. There are exciting innovation opportunities to manipulate the timing of footwear energy and return. This study demonstrates the research value of quantifying time-series foot + footwear power, and points industry developers towards footwear innovation opportunities.
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Affiliation(s)
- Emily S Matijevich
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, AB, Canada
| | - Eric C Honert
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, AB, Canada
| | - Fan Yang
- Li Ning Sports Research Center, Beijing, China
| | - Wing-Kai Lam
- Department of Kinesiology, Shenyang Sport University, Shenyang, China
| | - Benno M Nigg
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, AB, Canada
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Sedran L, Bonnet X, Thomas-Pohl M, Loiret I, Martinet N, Pillet H, Paysant J. Quantification of push-off and collision work during step-to-step transition in amputees walking at self-selected speed: Effect of amputation level. J Biomech 2024; 163:111943. [PMID: 38244403 DOI: 10.1016/j.jbiomech.2024.111943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 12/14/2023] [Accepted: 01/07/2024] [Indexed: 01/22/2024]
Abstract
Maintaining forward walking during human locomotion requires mechanical joint work, mainly provided by the ankle-foot in non-amputees. In lower-limb amputees, their metabolic overconsumption is generally attributed to reduced propulsion. However, it remains unclear how altered walking patterns resulting from amputation affect energy exchange. The purpose of this retrospective study was to investigate the impact of self-selected walking speed (SSWS) on mechanical works generated by the ankle-foot and by the entire lower limbs depending on the level of amputation. 155 participants, including 47 non-amputees (NAs), 40 unilateral transtibial amputees (TTs) and 68 unilateral transfemoral amputees (TFs), walked at their SSWS. Positive push-off work done by the trailing limb (WStS+) and its associated ankle-foot (Wankle-foot+), as well as negative collision work done by the leading limb (WStS-) were analysed during the transition from prosthetic limb to contralateral limb. An ANCOVA was performed to assess the effect of amputation level on mechanical works, while controlling for SSWS effect. After adjusting for SSWS, NAs produce more push-off work with both their biological ankle-foot and trailing limb than amputees do on prosthetic side. Using the same type of prosthetic feet, TTs and TFs can generate the same amount of prosthetic Wankle-foot+, while prosthetic WStS+ is significantly higher for TTs and remains constant with SSWS for TFs. Surprisingly and contrary to theoretical expectations, the lack of propulsion at TFs' prosthetic limb did not affect their contralateral WStS-, for which a difference is significant only between NAs and TTs. Further studies should investigate the relationship between the TFs' inability to increase prosthetic limb push-off work and metabolic expenditure.
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Affiliation(s)
- L Sedran
- Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers Sciences et Technologies, Paris, France; Proteor, Recherche & Développement, Dijon, France.
| | - X Bonnet
- Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers Sciences et Technologies, Paris, France
| | - M Thomas-Pohl
- Service de Médecine Physique et de Réadaptation, Hôpital d'Instruction des Armées Percy, Clamart, France; Service de Médecine Physique et de Réadaptation, Centre hospitalier de Cayenne Andrée Rosemon, Cayenne, France
| | - I Loiret
- Centre de médecine physique et de réadaptation Louis Pierquin IRR-UGECAM, Nord-Est 54042 Nancy Cedex, France
| | - N Martinet
- Centre de médecine physique et de réadaptation Louis Pierquin IRR-UGECAM, Nord-Est 54042 Nancy Cedex, France
| | - H Pillet
- Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers Sciences et Technologies, Paris, France
| | - J Paysant
- Centre de médecine physique et de réadaptation Louis Pierquin IRR-UGECAM, Nord-Est 54042 Nancy Cedex, France
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11
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Kawakami W, Iwamoto Y, Sekiya J, Ota M, Ishii Y, Takahashi M. Impact of pronated foot on energetic behavior and efficiency during walking. Gait Posture 2024; 107:23-27. [PMID: 37717290 DOI: 10.1016/j.gaitpost.2023.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 08/13/2023] [Accepted: 09/06/2023] [Indexed: 09/19/2023]
Abstract
BACKGROUND The longitudinal arch of the foot acts like a spring during stance and contributes to walking efficiency. Pronated foot characterized by a collapsed medial longitudinal arch may have the impaired spring-like function and poor walking efficiency. However, the differences in the energetic behavior during walking between individuals with pronated foot and neutral foot have not been considered. RESEARCH QUESTION How does the energetic behavior within the foot and proximal lower limb joints in pronated foot affect walking efficiency? METHODS Twenty-one healthy young adults were classified into neutral foot and pronated foot based on the Foot Posture Index score. All subjects walked across the floor and attempted to have the rearfoot and forefoot segments contact separate force plates to analyze the forces acting on isolated regions within the foot. Kinematic and kinetic data were recorded by a three-dimensional motion capture system. The hip, knee, ankle, and mid-tarsal joint power was quantified using a 6-degree-of-freedom joint power method. To qualify total power within all structures of the foot and forefoot, we used a unified deformable segment analysis. Additionally, we calculated the center of mass power to quantify the total power of the whole body RESULTS: There is no difference in the mid-tarsal joint work between the pronated foot and neutral foot. On the other hand, pronated foot exhibited greater net negative work at structures distal to the forefoot during walking. Additionally, pronated foot exhibited less net positive work at the ankle and center of mass during walking compared to neutral foot. SIGNIFICANCE Individuals with pronated foot generate the mid-tarsal joint work by increasing the work absorbed at structures distal to the forefoot, which results in reduced energy efficiency during walking. That energy inefficiency may reduce positive work at the ankle and affect the walking efficiency in individuals with pronated foot.
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Affiliation(s)
- Wataru Kawakami
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Yoshitaka Iwamoto
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; Center for Advanced Practice and Research of Rehabilitation, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Junpei Sekiya
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Mitsuhiro Ota
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Yosuke Ishii
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; Center for Advanced Practice and Research of Rehabilitation, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Makoto Takahashi
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; Center for Advanced Practice and Research of Rehabilitation, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
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12
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Bisele M, Bencsik M, Lewis MGC, Barnett CT. Attempted symmetry affects dynamic gait stability in individuals with lower-limb amputation. Gait Posture 2024; 107:182-188. [PMID: 37949725 DOI: 10.1016/j.gaitpost.2023.09.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 08/16/2023] [Accepted: 09/28/2023] [Indexed: 11/12/2023]
Abstract
BACKGROUND Gait in people with lower limb amputation (LLA) is typically asymmetrical. Reducing this asymmetry is often attempted to minimise the impact of secondary health issues. However, temporal-spatial asymmetry in gait of people with LLA has also been shown to underpin dynamic stability. RESEARCH QUESTION The current study aimed to identify the effects of acute attempts to achieve temporal-spatial symmetry on the dynamic stability of people with unilateral transtibial amputation (UTA). The secondary aim of this study was to identify the corresponding biomechanical adaptations during attempted symmetrical gait. METHODS Eleven people with UTA walked along a 15 m walkway in four different conditions: normal (NORM), attempted symmetrical step length and step frequency (SYMSL+SF) attempted symmetrical step length (SYMSL) and attempted symmetrical step frequency (SYMSF). Dynamic stability was measured using the backward (BW) and medio-lateral (ML) margins of stability (MoS). RESULTS Results indicate that attempting SYMSF had a positive effect on gait stability in BW and ML directions, while attempting SYMSL had a potentially negative effect, although these results did not appear to be significant. The absence of clustering in principal component analysis, supported the lack of significant results, indicating no features differentiating between conditions of attempted symmetry. Conversely, there was clustering by limbs which were associated with differences in knee and ankle joint angles between the prosthetic and non-prosthetic limbs, and clustering by individuals highlighting the importance of patient-specific analysis. CONCLUSION The data suggests that attempted symmetrical gait reduces asymmetry but also affects dynamic stability.
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Affiliation(s)
- Maria Bisele
- BG Klinik Ludwigshafen, Ludwigshafen am Rhein, Germany.
| | - Martin Bencsik
- School of Science and Technology, Nottingham Trent University, Nottingham, UK
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13
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Huang S, Teater RH, Zelik KE, McDonald KA. Biomechanical effects of an articulating prosthetic toe joint during stair navigation for individuals with unilateral, below-knee limb loss. J Biomech 2023; 161:111841. [PMID: 37907051 DOI: 10.1016/j.jbiomech.2023.111841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 10/15/2023] [Accepted: 10/19/2023] [Indexed: 11/02/2023]
Abstract
Stair navigation is an essential and demanding form of locomotion. During stair ascent and descent, persons with lower limb loss exhibit gait characteristics which may increase their risk of falls and joint degeneration of the intact limb. To reduce deviations from typically-able-bodied gait and overloading of the intact limb for this population, one potential intervention involves modifying passive prosthetic feet by incorporating a flexible toe joint that simulates the biological metatarsophalangeal joint. In this study, we aimed to assess the user preferences and biomechanical effects of a flexible prosthetic toe joint during stair ascent and descent for persons with unilateral lower-limb loss. Nine participants with unilateral lower-limb loss were recruited (Male; Medicare Functional Classification Level: eight K4, one K3; age: 41 ± 11 years; mass: 95 ± 13 kg; height: 1.84 ± 0.05 m; mean ± SD). No significant changes in lower-limb joint mechanics were identified. Five of nine participants preferred the unmodified prosthesis with a standard carbon fiber keel for both stair ascent and descent. Varied user preferences and inconsistent changes in lower-limb joint parameters between participants highlight the importance of subject-specific analyses and individualized device prescription.
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Affiliation(s)
- Sitan Huang
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37212, USA
| | - Rachel H Teater
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37212, USA
| | - Karl E Zelik
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37212, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37212, USA; Department of Physical Medicine and Rehabilitation, Vanderbilt University, Nashville, TN 37212, USA
| | - Kirsty A McDonald
- School of Health Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
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14
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Slater C, Hafner BJ, Morgan SJ. Effects of high-profile crossover feet on gait biomechanics in 2 individuals with Syme amputation. Prosthet Orthot Int 2023:00006479-990000000-00188. [PMID: 37870369 DOI: 10.1097/pxr.0000000000000295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 08/23/2023] [Indexed: 10/24/2023]
Abstract
BACKGROUND Prosthetic treatment options for people with ankle disarticulation (i.e., Syme amputation) are limited. Prosthetic feet designed for people with Syme amputation are often low profile to accommodate build-height restrictions, resulting in decreased energy return during gait. High-profile crossover feet that attach to the posterior proximal aspect of the prosthetic socket can bypass these restrictions and may promote a more physiologic gait pattern. OBJECTIVES To compare level-ground gait biomechanics and patient-reported outcomes between crossover and traditional energy-storing feet in people with Syme amputation. STUDY DESIGN Within-participant pilot study. METHODS Both participants were fit with energy-storing and crossover feet and were randomized to the order they used the feet. Participants used each foot for 2 weeks before assessment. Step length symmetry, prosthetic ankle range of motion, prosthetic-side energy return, and peak sound-side loading were determined from motion capture data obtained in a laboratory. Mobility and balance confidence were measured using standardized patient-reported outcome measures. Foot preference was assessed with an ad hoc survey. RESULTS Two participants with Syme amputations completed the study. Prosthetic ankle peak dorsiflexion and push-off power increased with the crossover foot compared with the energy-storing foot for both participants. Both participants reported an overall preference of the crossover foot. Changes in patient-reported outcomes did not exceed published minimum detectable change values. CONCLUSION Crossover feet increased prosthetic ankle range of motion and energy return compared with traditional energy-storing feet in this pilot investigation of 2 participants. Crossover feet seem to promote physiologic gait and may be a promising alternative to traditional low-profile feet for people with Syme amputation.
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Affiliation(s)
- Conrad Slater
- Department of Rehabilitation Medicine, University of Washington, Seattle, WA
- Present affiliation: Hanger Clinic, Olympia, WA
| | - Brian J Hafner
- Department of Rehabilitation Medicine, University of Washington, Seattle, WA
| | - Sara J Morgan
- Department of Rehabilitation Medicine, University of Washington, Seattle, WA
- Present affiliation: Research Department, Gillette Children's Specialty Healthcare, Saint Paul, MN
- Present affiliation: Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN
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15
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Papachatzis N, Takahashi KZ. Mechanics of the human foot during walking on different slopes. PLoS One 2023; 18:e0286521. [PMID: 37695795 PMCID: PMC10495022 DOI: 10.1371/journal.pone.0286521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 05/17/2023] [Indexed: 09/13/2023] Open
Abstract
When humans walk on slopes, the ankle, knee, and hip joints modulate their mechanical work to accommodate the mechanical demands. Yet, it is unclear if the foot modulates its work output during uphill and downhill walking. Therefore, we quantified the mechanical work performed by the foot and its subsections of twelve adults walked on five randomized slopes (-10°, -5°, 0°, +5°, +10°). We estimated the work of distal-to-hindfoot and distal-to-forefoot structures using unified deformable segment analysis and the work of the midtarsal, ankle, knee, and hip joints using a six-degree-of-freedom model. Further, using a geometric model, we estimated the length of the plantar structures crossing the longitudinal arch while accounting for the first metatarsophalangeal wrapping length. We hypothesized that compared to level walking, downhill walking would increase negative and net-negative work magnitude, particularly at the early stance phase, and uphill walking would increase the positive work, particularly at the mid-to-late stance phase. We found that downhill walking increased the magnitude of the foot's negative and net-negative work, especially during early stance, highlighting its capacity to absorb impacts when locomotion demands excessive energy dissipation. Notably, the foot maintained its net dissipative behavior between slopes; however, the ankle, knee, and hip shifted from net energy dissipation to net energy generation when changing from downhill to uphill. Such results indicate that humans rely more on joints proximal to the foot to modulate the body's total mechanical energy. Uphill walking increased midtarsal's positive and distal-to-forefoot negative work in near-equal amounts. That coincided with the prolonged lengthening and delayed shortening of the plantar structures, resembling a spring-like function that possibly assists the energetic demands of locomotion during mid-to-late stance. These results broaden our understanding of the foot's mechanical function relative to the leg's joints and could inspire the design of wearable assistive devices that improve walking capacity.
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Affiliation(s)
- Nikolaos Papachatzis
- Department of Mechanical Engineering & Materials Science, Yale University, New Haven, Connecticut, United States of America
- Department of Biomechanics, University of Nebraska at Omaha, Omaha, Nebraska, United States of America
| | - Kota Z. Takahashi
- Department of Health & Kinesiology, University of Utah, Salt Lake City, Utah, United States of America
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16
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Banks BP, Frei JS, Spencer A, Renninger KD, Grover JK, Abbott K, Carlson BJ, Bruening DA. Low-cost prosthetic feet for underserved populations: A comparison of gait analysis and mechanical stiffness. Prosthet Orthot Int 2023; 47:399-406. [PMID: 36701193 DOI: 10.1097/pxr.0000000000000184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 08/17/2022] [Indexed: 01/27/2023]
Abstract
BACKGROUND Lower-limb loss is an ongoing cause of disability throughout the world. Despite advancements in prosthetic technologies, there are numerous underserved populations in need of effective low-cost prosthetic foot options. OBJECTIVE To evaluate the biomechanical performance of several low-cost prosthetic feet, using a combination of instrumented gait analysis and mechanical stiffness testing. STUDY DESIGN Randomized crossover with additional case study. METHODS We compared the solid-ankle-cushioned-heel (SACH), Jaipur, and Niagara feet with carbon fiber feet. Mechanical stiffness was evaluated using a cantilever-style bending test at 2 angles that was designed to mimic late stance gait loading. Eight below-knee amputees participated in the gait analysis, which focused on foot and ankle motion and energetics. RESULTS Metric analysis showed significant differences among feet in ankle motion and power as well as distal-to-shank power, with SACH showing reduced ankle motion and positive work compared with the other feet. Waveform analysis additionally revealed a compensatory knee flexion moment in SACH and a knee extension moment in Niagara and Jaipur during midstance. In mechanical stiffness testing, SACH had the highest stiffness, with Niagara and carbon fiber roughly similar, and Jaipur the most compliant with the greatest hysteresis. CONCLUSIONS There may be an optimal stiffness range for future prosthesis designs that maximizes propulsive energy. This may be achieved by combining some characteristics of Jaipur and Niagara feet in new designs. Ultimately, optimizing stiffness and energetics for gait biomimicry while maintaining cost, availability, and versatility across cultures will alleviate the effects of limb loss among underserved populations.
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Affiliation(s)
- Brevin P Banks
- Mechanical Engineering Department, Brigham Young University, Provo, UT, USA
| | - Joshua S Frei
- Chemical Engineering Department, Brigham Young University, Provo, UT, USA
| | - Alyssa Spencer
- Mechanical Engineering Department, Brigham Young University, Provo, UT, USA
| | | | - Jordan K Grover
- Exercise Sciences Department, Brigham Young University, Provo, UT, USA
| | - Kaitlin Abbott
- Exercise Sciences Department, Brigham Young University, Provo, UT, USA
| | | | - Dustin A Bruening
- Exercise Sciences Department, Brigham Young University, Provo, UT, USA
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17
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Heitzmann DWW, Block J, Trinler U, Wolf SI, Alimusaj M. [Motion analysis in lower limb exoprosthetics-possibilities and limitations]. ORTHOPADIE (HEIDELBERG, GERMANY) 2023:10.1007/s00132-023-04408-z. [PMID: 37458809 DOI: 10.1007/s00132-023-04408-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/12/2023] [Indexed: 07/25/2023]
Abstract
BACKGROUND Gait analysis is of high relevance in prosthetics as it is an essential part of the fitting process. The documentation of movement by means of videos and instrumented methods is becoming increasingly important in prosthetics as benefits of a complex prosthesis can best be shown by structured observation. PROCEDURE A movement analysis should always be preceded by an anamnesis and clinical examination in order to detect functional limitations of the examined person and thus to establish correlations to gait deviations. Additionally, the orthopaedic aid should be evaluated as well. In addition to walking on level ground, walking on everyday obstacles such as stairs and ramps is also of interest when observing people using prosthetic limbs. Functional tests can be used to determine the functional status more comprehensively. An instrumental-3D gait analysis is indicated for specific questions, especially regarding kinetic parameters.
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Affiliation(s)
- Daniel Walter Werner Heitzmann
- Abteilungen Technische Orthopädie und Bewegungsanalytik, Klinik für Orthopädie, Universitätsklinikum Heidelberg, Schlierbacher Landstr. 200a, 69118, Heidelberg, Deutschland.
| | - Julia Block
- Abteilungen Technische Orthopädie und Bewegungsanalytik, Klinik für Orthopädie, Universitätsklinikum Heidelberg, Schlierbacher Landstr. 200a, 69118, Heidelberg, Deutschland
| | - Ursula Trinler
- Andreas Wentzensen Forschungsinstitut, BG Klinik Ludwigshafen, Ludwigshafen, Deutschland
| | - Sebastian I Wolf
- Abteilungen Technische Orthopädie und Bewegungsanalytik, Klinik für Orthopädie, Universitätsklinikum Heidelberg, Schlierbacher Landstr. 200a, 69118, Heidelberg, Deutschland
| | - Merkur Alimusaj
- Abteilungen Technische Orthopädie und Bewegungsanalytik, Klinik für Orthopädie, Universitätsklinikum Heidelberg, Schlierbacher Landstr. 200a, 69118, Heidelberg, Deutschland
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18
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Cyr KM, Segal AD, Neptune RR, Klute GK. Biomechanical responses of individuals with transtibial amputation stepping on a coronally uneven and unpredictable surface. J Biomech 2023; 155:111622. [PMID: 37247517 DOI: 10.1016/j.jbiomech.2023.111622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 03/13/2023] [Accepted: 05/05/2023] [Indexed: 05/31/2023]
Abstract
Coronally uneven surfaces are prevalent in natural and man-made terrain, such as holes or bumps in the ground, curbs, sidewalks, and driveways. These surfaces can be challenging to navigate, especially for individuals with lower limb amputations. This study examined the biomechanical response of individuals with unilateral transtibial amputation (TTA) taking a step on a coronally uneven surface while wearing their clinically prescribed prosthesis, compared to individuals without mobility impairments (controls). An instrumented walkway was used with the middle force plate positioned either flush or rotated ± 15˚ in the coronal plane and concealed (blinded). TTAs used greater hip abduction compared to controls across all conditions, but especially during blinded inversion. The recovery step width of TTAs was wider after blinded eversion and narrower after blinded inversion, but unchanged for controls. These results suggest TTAs may have decreased balance control on unexpected, uneven surfaces. Additionally, TTAs generated less positive prosthetic ankle joint work during blinded inversion and eversion, and less negative coronal hip joint work during blinded inversion compared to controls. These biomechanical responses could lead to increased energy expenditure on uneven terrain. Surface condition had no effect on the vertical center of mass for either group of participants. Finally, the TTAs and the control group generated similar vertical GRF impulses, suggesting the TTAs had sufficient body support despite differences in surface conditions. These results are important to consider for future prosthetic foot designs and rehabilitation strategies.
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Affiliation(s)
- Krista M Cyr
- Department of Veterans Affairs Center for Limb Loss and MoBility, Seattle, WA, USA
| | - Ava D Segal
- Department of Mechanical Engineering, Colorado School of Mines, Golden, CO, USA
| | - Richard R Neptune
- Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Glenn K Klute
- Department of Veterans Affairs Center for Limb Loss and MoBility, Seattle, WA, USA; Department of Mechanical Engineering, University of Washington, Seattle, WA, USA.
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19
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Biomechanical comparison of a 3D-printed prosthetic foot with conventional feet in people with transtibial amputation: A prospective cohort study. Prosthet Orthot Int 2023; 47:94-100. [PMID: 36018858 DOI: 10.1097/pxr.0000000000000180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 06/24/2022] [Indexed: 02/03/2023]
Abstract
INTRODUCTION The method of 3D printing is increasingly gaining utilization in clinical applications and may support prosthetic fitting. The aim was to compare biomechanical outcomes of people with a transtibial amputation using a novel, individualizable, 3D-printed prosthetic foot (ComfyStep, Mecuris) with two conventional, widely used prosthetic feet during level ground walking using a 3D motion analysis system. METHODS Ten individuals with an unilateral transtibial amputation were fitted with 3 prosthetic feet (ComfyStep, Assure/Össur, DynamicMotion/Ottobock) using their current, well-fitting socket. They had at least 1 week of familiarization for each foot before gait analyses were conducted. Kinematics and kinetics as well as roll over shape (ROS) length and radius were calculated and compared between feet. RESULTS The sound side gait parameters of the participants were comparable when using different feet. However, there were differences on the affected side. The statistical analysis revealed that the 3D-printed foot differed significantly compared with the conventional feet in the following aspects: reduced range of motion, increased plantar flexion moment, reduced plantar flexion power, larger ROS radius, less favorable energy ratio, and higher overall stiffness. CONCLUSION In principle, 3D-printed feet have advantages over conventional "off the shelf" feet, as their biomechanical characteristics could be adjusted more in detail according to the patient needs. Although, differences between conventional feet and the ComfyStep were shown. Whether these differences have a negative clinically relevant effect remains unclear. However, results suggest that commercially available 3D-printed feet should incorporate systematically better adjustments, for example, for stiffness, to enhance prosthetic performance.
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20
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Nichols KM, Adamczyk PG. Sensitivity of lower-limb joint mechanics to prosthetic forefoot stiffness with a variable stiffness foot in level-ground walking. J Biomech 2023; 147:111436. [PMID: 36701959 PMCID: PMC11286132 DOI: 10.1016/j.jbiomech.2023.111436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 12/14/2022] [Accepted: 01/04/2023] [Indexed: 01/15/2023]
Abstract
This paper presents the effectsof the Variable Stiffness Foot (VSF) on lower-limb joint mechanics in level-ground walking. Persons with transtibial amputations use lower-limb prostheses to restore level-ground walking, and foot stiffness and geometry have been shown to be the main factors for evaluating foot prostheses. Previous studies have validated the semi-active and stiffness modulation capabilities of the VSF. The core aim of this study is to investigate the mechanical effects of adjusting stiffness on knee and ankle mechanics for prosthetic users wearing the VSF. For this study, seven human participants walked with three different stiffnesses (compliant, medium, stiff) of the VSF across two force plates in a motion capture lab. Linear mixed models were utilized to estimate the significance and coefficients of determinations for the regression of stiffness on several biomechanical metrics. A stiffer VSF led to decreased ankle dorsiflexion angle (p < 0.0001, r2 = 0.90), increased ankle plantarflexor moment (p = 0.016, r2 = 0.40), increased knee extension (p = 0.021, r2 = 0.37), increased knee flexor moment (p = 0.0007, r2 = 0.63), and decreased magnitudes of prosthetic energy storage (p < 0.0001, r2 = 0.90), energy return (p = 0.0003, r2 = 0.67), and power (p < 0.0001, r2 = 0.74). These results imply lower ankle, knee, and hip moments, and more ankle angle range of motion using a less stiff VSF, which may be advantageous to persons walking with lower-limb prostheses. Responsive modulation of the VSF stiffness, according to these findings, could help overcome gait deviations associated with different slopes, terrain characteristics, or footwear.
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Affiliation(s)
- Kieran M Nichols
- University of Wisconsin-Madison Department of Mechanical Engineering, Room 3034, Mechanical Engineering Building, 1513 University Ave., Madison, WI 53706-1539, United States.
| | - Peter G Adamczyk
- University of Wisconsin-Madison Department of Mechanical Engineering, Room 3039, Mechanical Engineering Building, 1513 University Ave., Madison, WI 53706-1539, United States.
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21
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Running footstrike pattern effect on lower extremity work in an individual with transtibial amputation. Prosthet Orthot Int 2022; 46:549-552. [PMID: 36515901 DOI: 10.1097/pxr.0000000000000158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 03/14/2022] [Indexed: 02/03/2023]
Abstract
Asymmetrical loading favoring the intact limb during running has been associated with increased prevalence of reported knee pain and potential risk factors of knee osteoarthritis in that limb for patients with amputation. Footstrike pattern alterations have been suggested to help alleviate some overloading of the knee, but little is known about how it affects the rest of the limb. The purpose of this case study was to evaluate the effect of footstrike pattern on the distribution of loading throughout the lower extremities during submaximal running of an individual with transtibial amputation (TTA). This study compared loading distribution among the lower extremity joints in a male patient who sustained a TTA and ran using both a rearfoot (RFS) and forefoot strike (FFS) pattern. The results of this case demonstrated that altering footstrike pattern minimally alters the total mechanical work being done by the lower extremities but more so affects the relative amount of work contributed by the individual joints. In the intact limb, the ankle contributes the most to power absorption using a FFS pattern while the knee has a larger role using a RFS pattern. This case suggests that the footstrike pattern affects lower extremity loading distribution at the joint level, and adopting a FFS pattern may alleviate overloading the knee, whereas a RFS pattern may reduce loading at the ankle in individuals with TTA.
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22
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Barnett CT, De Asha AR, Skervin TK, Buckley JG, Foster RJ. Spring-mass behavioural adaptations to acute changes in prosthetic blade stiffness during submaximal running in unilateral transtibial prosthesis users. Gait Posture 2022; 98:153-159. [PMID: 36126535 DOI: 10.1016/j.gaitpost.2022.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 08/20/2022] [Accepted: 09/09/2022] [Indexed: 02/02/2023]
Abstract
BACKGROUND Individuals with lower-limb amputation can use running specific prostheses (RSP) that store and then return elastic energy during stance. However, it is unclear whether varying the stiffness category of the same RSP affects spring-mass behaviour during self-selected, submaximal speed running in individuals with unilateral transtibial amputation. RESEARCH QUESTION The current study investigates how varying RSP stiffness affects limb stiffness, running performance, and associated joint kinetics in individuals with a unilateral transtibial amputation. METHODS Kinematic and ground reaction force data were collected from eight males with unilateral transtibial amputation who ran at self-selected submaximal speeds along a 15 m runway in three RSP stiffness conditions; recommended habitual stiffness (HAB) and, following 10-minutes of familiarisation, stiffness categories above (+1) and below (-1) the HAB. Stance-phase centre of mass velocity, contact time, limb stiffness' and joint/RSP work were computed for each limb across RSP stiffness conditions. RESULTS With increased RSP stiffness, prosthetic limb stiffness increased, whilst intact limb stiffness decreased slightly (p<0.03). Centre of mass forward velocity during stance-phase (p<0.02) and contact time (p<0.04) were higher in the intact limb and lower in the prosthetic limb but were unaffected by RSP stiffness. Intact limb hip joint positive work increased for both the +1 and -1 conditions but remained unchanged across conditions in the prosthetic limb (p<0.02). SIGNIFICANCE In response to changes in RSP stiffness, there were acute increased mechanical demands on the intact limb, reflecting a reliance on the intact limb during running. However, overall running speed was unaffected, suggesting participants acutely adapted to an RSP of a non-prescribed stiffness.
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Affiliation(s)
- C T Barnett
- School of Science and Technology, Nottingham Trent University, Nottingham, UK.
| | - A R De Asha
- School of Science and Technology, Nottingham Trent University, Nottingham, UK; C-Motion, Inc., Germantown, MD, USA
| | - T K Skervin
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, UK
| | - J G Buckley
- Department of Biomedical & Electronics Engineering, University of Bradford, Bradford, UK
| | - R J Foster
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, UK
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23
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Metatarsophalangeal Joint Dynamic Stiffness During Toe Rocker Changes With Walking Speed. J Appl Biomech 2022; 38:320-327. [PMID: 36096476 DOI: 10.1123/jab.2021-0385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 05/30/2022] [Accepted: 07/06/2022] [Indexed: 11/18/2022]
Abstract
Dynamic joint stiffness (or simply "stiffness") is a customization criteria used to tune mechanical properties of orthotic and prosthetic devices. This study examines metatarsophalangeal (MTP) joint stiffness during the toe-rocker phase of barefoot walking and establishes baseline characteristics of MTP joint stiffness. Ten healthy individuals walked at 4 speeds (0.4, 0.6, 0.8, and 1.0 statures·s-1) over level ground. MTP sagittal plane joint angles and moments were calculated during the toe-rocker phase of stance. Least-squares linear regressions were conducted on the MTP moment versus angle curve to determine joint stiffness during early toe rocker and late toe rocker. Multilevel linear models were used to test for statistically significant differences between conditions. Early toe rocker stiffness was positive, while late toe rocker was negative. Both early toe rocker and late toe rocker stiffness increased in magnitude significantly with speed. This study establishes baseline characteristics of MTP joint stiffness in healthy walking, which previously had not been examined through a range of controlled walking speeds. This information can be used in the future as design criteria for orthotic and prosthetic ankle and ankle-foot devices that can imitate, support, and facilitate natural human foot motion during walking better than existing devices.
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Methods of Estimating Foot Power and Work in Standing Vertical Jump. J Appl Biomech 2022; 38:293-300. [PMID: 36007877 DOI: 10.1123/jab.2021-0254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 06/11/2022] [Accepted: 06/24/2022] [Indexed: 12/31/2022]
Abstract
Experimental motion capture studies have commonly considered the foot as a single rigid body even though the foot contains 26 bones and 30 joints. Various methods have been applied to study rigid body deviations of the foot. This study compared 3 methods: distal foot power (DFP), foot power imbalance (FPI), and a 2-segment foot model to study foot power and work in the takeoff phase of standing vertical jumps. Six physically active participants each performed 6 standing vertical jumps from a starting position spanning 2 adjacent force platforms to allow ground reaction forces acting on the foot to be divided at the metatarsophalangeal (MTP) joints. Shortly after movement initiation, DFP showed a power absorption phase followed by a power generation phase. FPI followed a similar pattern with smaller power absorption and a larger power generation compared to DFP. MTP joints primarily generated power in the 2-segment model. The net foot work was -4.0 (1.0) J using DFP, 1.8 (1.1) J using FPI, and 5.1 (0.5) J with MTP. The results suggest that MTP joints are only 1 source of foot power and that differences between DFP and FPI should be further explored in jumping and other movements.
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Hu D, Xiong C, Wang T, Zhou T, Liang J, Li Y. Modulating Energy Among Foot-Ankle Complex With an Unpowered Exoskeleton Improves Human Walking Economy. IEEE Trans Neural Syst Rehabil Eng 2022; 30:1961-1970. [PMID: 35793296 DOI: 10.1109/tnsre.2022.3188870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Over the course of both evolution and development, the human musculoskeletal system has been well shaped for the cushion function of the foot during foot-strike and the impulsive function of the ankle joint during push-off. Nevertheless, an efficient energy interaction between foot structure and ankle joint is still lacking in the human body itself, which may limit the further potential of economical walking. Here we showed the metabolic expenditure of walking can be lessened by an unpowered exoskeleton robot that modulates energy among the foot-ankle complex towards a more effective direction. The unpowered exoskeleton recycles negative mechanical energy of the foot that is normally dissipated in heel-strike, retains the stored energy before mid-stance, and then transfers the energy to the ankle joint to assist the push-off. The modulation process of the exoskeleton consumes no input energy, yet reduces the metabolic cost of walking by 8.19 ± 0.96 % (mean ± s.e.m) for healthy subjects. The electromyography measurements demonstrate the activities of target ankle plantarflexors decreased significantly without added effort for the antagonistic muscle, suggesting the exoskeleton enhanced the subjects' energy efficiency of the foot-ankle complex in a natural manner. Furthermore, the exoskeleton also provides cushion assistance for walking, which leads to significantly decreased activity of the quadriceps muscle during heel-strike. Rather than strengthening the functions of existing biological structures, developing the complementary energy loop that does not exist in the human body itself also shows its potential for gait assistance.
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A foot and footwear mechanical power theoretical framework: towards understanding energy storage and return in running footwear. J Biomech 2022; 141:111217. [DOI: 10.1016/j.jbiomech.2022.111217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 06/28/2022] [Accepted: 06/30/2022] [Indexed: 11/18/2022]
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Unilateral below-knee prosthesis users walking on uneven terrain: The effect of adding a toe joint to a passive prosthesis. J Biomech 2022; 138:111115. [DOI: 10.1016/j.jbiomech.2022.111115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 04/28/2022] [Accepted: 04/28/2022] [Indexed: 11/30/2022]
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Runciman P, Cockcroft J, Derman W. A novel pivot ankle/foot prosthesis reduces sound side loading and risk for osteoarthritis: a pragmatic randomized controlled trial. Prosthet Orthot Int 2022; 46:258-266. [PMID: 35019886 PMCID: PMC9201932 DOI: 10.1097/pxr.0000000000000079] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 09/21/2021] [Accepted: 11/01/2021] [Indexed: 02/03/2023]
Abstract
BACKGROUND Individuals with unilateral transtibial amputation are at risk of abnormal mechanical joint loading and development of osteoarthritis on sound side joint structures. OBJECTIVES This study describes the spatiotemporal and kinetic and kinematic parameters related to osteoarthritis in participants while using (A) a solid-ankle cushioned-heel prosthesis (SACH), (B) a conventional energy storage and return (ESAR) foot prosthesis, and (C) a novel ESAR (N-ESAR) foot prosthesis. STUDY DESIGN A pragmatic randomized controlled trial. METHODS K3-K4 ambulators used three feet in a 2-week randomized cross-over order. Kinetics of vertical ground reaction forces (vGRFs) and 3D kinematics of joint angles were integrated to provide normalized parameters. Data were analyzed using one way and mixed model Analysis of variance (ANOVAs) (p < 0.05) and Cohen d statistic. RESULTS Twenty participants, aged 40 ± 16 years with body mass index of 24.7 ± 3.6 kg/m2, experienced minimal change in the spatiotemporal parameters between feet. Participants using the N-ESAR foot prosthesis experienced reduced peak knee external adduction moment (p = 0.030), peak vGRFs (p < 0.001), and peak loading rate of vGRFs (p = 0.030). Peak knee flexion moments only changed when using the solid-ankle cushioned-heel prosthesis, in a positive direction (p = 0.014). Using the N-ESAR prosthesis also increased peak distal shank power during late stance phase (p < 0.001). CONCLUSIONS A novel ankle/foot ESAR prosthesis reduces loading on the sound side. With extended use of the N-ESAR foot prosthesis, these findings may provide the prosthesis user with improved outcomes related to sound side loading and development of osteoarthritis.
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Affiliation(s)
- Phoebe Runciman
- Department of Sport Science, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
- Institute of Sport and Exercise Medicine, Department of Surgical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
| | - John Cockcroft
- Institute of Sport and Exercise Medicine, Department of Surgical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
- Neuromechanics Unit, Central Analytics Facilities, Stellenbosch University, Stellenbosch, South Africa
| | - Wayne Derman
- Institute of Sport and Exercise Medicine, Department of Surgical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
- International Olympic Committee (IOC) Research Centre, Cape Town, South Africa
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Golyski PR, Sawicki GS. Which lower limb joints compensate for destabilizing energy during walking in humans? J R Soc Interface 2022; 19:20220024. [PMID: 35642426 PMCID: PMC9156907 DOI: 10.1098/rsif.2022.0024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 05/04/2022] [Indexed: 11/12/2022] Open
Abstract
Current approaches to investigating stabilizing responses during locomotion lack measures that both directly relate to perturbation demands and are shared across different levels of description (i.e. joints and legs). Here, we investigated whether mechanical energy could serve as a 'common currency' during treadmill walking with transient unilateral belt accelerations. We hypothesized that by delivering perturbations in either early or late stance, we could elicit net negative or positive work, respectively, from the perturbed leg at the leg/treadmill interface, which would dictate the net demand at the overall leg level. We further hypothesized that of the lower limb joints, the ankle would best reflect changes in overall leg work. On average across all seven participants and 222 perturbations, we found early stance perturbations elicited no change in net work performed by the perturbed leg on the treadmill, but net positive work by the overall leg, which did not support our hypotheses. Conversely, late stance perturbations partially supported our hypotheses by eliciting positive work at the leg/treadmill interface, but no change in net work by the overall leg. In support of our final hypothesis, changes in perturbed ankle work, in addition to contralateral knee work, best reflected changes in overall leg work.
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Affiliation(s)
- Pawel R. Golyski
- Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA, USA
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Gregory S. Sawicki
- Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA, USA
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
- Institute for Robotics and Intelligent Machines, Georgia Institute of Technology, Atlanta, GA, USA
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
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Honert EC, Ostermair F, von Tscharner V, Nigg BM. Changes in ankle work, foot work, and tibialis anterior activation throughout a long run. JOURNAL OF SPORT AND HEALTH SCIENCE 2022; 11:330-338. [PMID: 33662603 PMCID: PMC9189696 DOI: 10.1016/j.jshs.2021.02.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 10/19/2020] [Accepted: 12/22/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND The ankle and foot together contribute to over half of the positive and negative work performed by the lower limbs during running. Yet, little is known about how foot kinetics change throughout a run. The amount of negative foot work may decrease as tibialis anterior (TA) electromyography (EMG) changes throughout longer-duration runs. Therefore, we examined ankle and foot work as well as TA EMG changes throughout a changing-speed run. METHODS Fourteen heel-striking subjects ran on a treadmill for 58 min. We collected ground reaction forces, motion capture, and EMG. Subjects ran at 110%, 100%, and 90% of their 10-km running speed and 2.8 m/s multiple times throughout the run. Foot work was evaluated using the distal rearfoot work, which provides a net estimate of all work contributors within the foot. RESULTS Positive foot work increased and positive ankle work decreased throughout the run at all speeds. At the 110% 10-km running speed, negative foot work decreased and TA EMG frequency shifted lower throughout the run. The increase in positive foot work may be attributed to increased foot joint work performed by intrinsic foot muscles. Changes in negative foot work and TA EMG frequency may indicate that the TA plays a role in negative foot work in the early stance of a run. CONCLUSION This study is the first to examine how the kinetic contributions of the foot change throughout a run. Future studies should investigate how increases in foot work affect running performance.
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Affiliation(s)
- Eric C Honert
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
| | - Florian Ostermair
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta T2N 1N4, Canada; Institute of Sports and Sports Science, Karlsruhe Institute of Technology, Karlsruhe 76131, Germany; Department of Sports Science and Sports, Friedrich Alexander University Erlangen-Nuremberg, Erlangen 91058, Germany
| | - Vinzenz von Tscharner
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Benno M Nigg
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta T2N 1N4, Canada
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Biomechanical evaluation over level ground walking of user-specific prosthetic feet designed using the lower leg trajectory error framework. Sci Rep 2022; 12:5306. [PMID: 35351910 PMCID: PMC8964743 DOI: 10.1038/s41598-022-09114-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 03/08/2022] [Indexed: 11/08/2022] Open
Abstract
The walking pattern and comfort of a person with lower limb amputation are determined by the prosthetic foot’s diverse set of mechanical characteristics. However, most design methodologies are iterative and focus on individual parameters, preventing a holistic design of prosthetic feet for a user’s body size and walking preferences. Here we refined and evaluated the lower leg trajectory error (LLTE) framework, a novel quantitative and predictive design methodology that optimizes the mechanical function of a user’s prosthesis to encourage gait dynamics that match their body size and desired walking pattern. Five people with unilateral below-knee amputation walked over-ground at self-selected speeds using an LLTE-optimized foot made of Nylon 6/6, their daily-use foot, and a standardized commercial energy storage and return (ESR) foot. Using the LLTE feet, target able-bodied kinematics and kinetics were replicated to within 5.2% and 13.9%, respectively, 13.5% closer than with the commercial ESR foot. Additionally, energy return and center of mass propulsion work were 46% and 34% greater compared to the other two prostheses, which could lead to reduced walking effort. Similarly, peak limb loading and flexion moment on the intact leg were reduced by an average of 13.1%, lowering risk of long-term injuries. LLTE-feet were preferred over the commercial ESR foot across all users and preferred over the daily-use feet by two participants. These results suggest that the LLTE framework could be used to design customized, high performance ESR prostheses using low-cost Nylon 6/6 material. More studies with large sample size are warranted for further verification.
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Smith RE, Lichtwark GA, Kelly LA. Flexor digitorum brevis utilises elastic strain energy to contribute to both work generation and energy absorption at the foot. J Exp Biol 2022; 225:274868. [PMID: 35344050 PMCID: PMC9124483 DOI: 10.1242/jeb.243792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 03/20/2022] [Indexed: 11/20/2022]
Abstract
The central nervous system utilizes tendon compliance of the intrinsic foot muscles to aid the foot's arch spring, storing and returning energy in its tendinous tissues. Recently, the intrinsic foot muscles have been shown to adapt their energetic contributions during a variety of locomotor tasks to fulfil centre of mass work demands. However, the mechanism by which the small intrinsic foot muscles are able to make versatile energetic contributions remains unknown. Therefore, we examined the muscle–tendon dynamics of the flexor digitorum brevis during stepping, jumping and landing tasks to see whether the central nervous system regulates muscle activation magnitude and timing to enable energy storage and return to enhance energetic contributions. In step-ups and jumps, energy was stored in the tendinous tissue during arch compression; during arch recoil, the fascicles shortened at a slower rate than the tendinous tissues while the foot generated energy. In step-downs and landings, the tendinous tissues elongated more and at greater rates than the fascicles during arch compression while the foot absorbed energy. These results indicate that the central nervous system utilizes arch compression to store elastic energy in the tendinous tissues of the intrinsic foot muscles to add or remove mechanical energy when the body accelerates or decelerates. This study provides evidence for an adaptive mechanism to enable the foot's energetic versatility and further indicates the value of tendon compliance in distal lower limb muscle–tendon units in locomotion. Summary: Demonstration of an adaptive mechanism that enables the intrinsic foot muscles to make versatile contributions to whole-body accelerations and decelerations.
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Affiliation(s)
- Ross E Smith
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Australia
| | - Glen A Lichtwark
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Australia
| | - Luke A Kelly
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Australia
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Williams LR, Ridge ST, Johnson AW, Arch ES, Bruening DA. The influence of the windlass mechanism on kinematic and kinetic foot joint coupling. J Foot Ankle Res 2022; 15:16. [PMID: 35172865 PMCID: PMC8848977 DOI: 10.1186/s13047-022-00520-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 02/09/2022] [Indexed: 11/16/2022] Open
Abstract
Background Previous research shows kinematic and kinetic coupling between the metatarsophalangeal (MTP) and midtarsal joints during gait. Studying the effects of MTP position as well as foot structure on this coupling may help determine to what extent foot coupling during dynamic and active movement is due to the windlass mechanism. This study’s purpose was to investigate the kinematic and kinetic foot coupling during controlled passive, active, and dynamic movements. Methods After arch height and flexibility were measured, participants performed four conditions: Seated Passive MTP Extension, Seated Active MTP Extension, Standing Passive MTP Extension, and Standing Active MTP Extension. Next, participants performed three heel raise conditions that manipulated the starting position of the MTP joint: Neutral, Toe Extension, and Toe Flexion. A multisegment foot model was created in Visual 3D and used to calculate ankle, midtarsal, and MTP joint kinematics and kinetics. Results Kinematic coupling (ratio of midtarsal to MTP angular displacement) was approximately six times greater in Neutral heel raises compared to Seated Passive MTP Extension, suggesting that the windlass only plays a small kinematic role in dynamic tasks. As the starting position of the MTP joint became increasingly extended during heel raises, the amount of negative work at the MTP joint and positive work at the midtarsal joint increased proportionally, while distal-to-hindfoot work remained unchanged. Correlations suggest that there is not a strong relationship between static arch height/flexibility and kinematic foot coupling. Conclusions Our results show that there is kinematic and kinetic coupling within the distal foot, but this coupling is attributed only in small measure to the windlass mechanism. Additional sources of coupling include foot muscles and elastic energy storage and return within ligaments and tendons. Furthermore, our results suggest that the plantar aponeurosis does not function as a rigid cable but likely has extensibility that affects the effectiveness of the windlass mechanism. Arch structure did not affect foot coupling, suggesting that static arch height or arch flexibility alone may not be adequate predictors of dynamic foot function. Supplementary Information The online version contains supplementary material available at 10.1186/s13047-022-00520-z.
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De Asha AR, Barnett CT. Calculated functional joint center positions are highly variable in individuals with unilateral transtibial amputation walking with identical prosthetic ankle-foot devices. Prosthet Orthot Int 2022; 46:91-94. [PMID: 34840279 DOI: 10.1097/pxr.0000000000000056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 08/09/2021] [Indexed: 02/03/2023]
Abstract
BACKGROUND Biomechanical modeling of the lower limbs, including prosthetic componentry, makes a number of assumptions that influence the data obtained and their subsequent interpretation. Calculated prosthetic ankle functional joint center (FJC) positions vary between devices and have been suggested as a possible method of comparing device function. OBJECTIVES The study aimed to assess the variability of joint center position estimates, calculated using an FJC methodology, in all three planes. This was assessed in participants with unilateral transtibial amputation using an identical prosthetic ankle-foot device during walking on a flat surface. STUDY DESIGN Case series. TECHNIQUE Three-dimensional motion capture recorded the position of markers placed on the shank and ankle-foot device of five individuals with unilateral transtibial amputation, as they completed 10 trials of level walking using the same ankle-foot device. The FJC between the prosthetic foot and shank segments were calculated for each trial. RESULTS The calculated FJC positions were highly variable across individual participants and within each individual. This variability was observed across all three planes of movement and resulted in calculated joint center positions created beyond the physical boundaries of the prosthetic device. CONCLUSIONS Biomechanical data are affected by lower limb and prosthetic device modeling assumptions. Definition of a prosthetic "ankle" joint using an FJC method results in highly variable "ankle" joint center positions when applied to a prosthetic ankle-foot device. Their use should be discouraged to avoid misleading interpretations of data.
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Affiliation(s)
- Alan R De Asha
- School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
- C-Motion, Inc, Germantown, MD
| | - Cleveland T Barnett
- School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
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Kline PW, So N, Fields T, Juarez-Colunga E, Christiansen CL. Error-Manipulation Gait Training for Veterans With Nontraumatic Lower Limb Amputation: A Randomized Controlled Trial Protocol. Phys Ther 2021; 101:6340853. [PMID: 34379777 PMCID: PMC8639646 DOI: 10.1093/ptj/pzab192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 04/30/2021] [Accepted: 07/05/2021] [Indexed: 11/14/2022]
Abstract
OBJECTIVE he purpose of this study will be to determine the efficacy of error-manipulation gait training (error-augmentation or error-correction) to improve step length symmetry and secondary health outcomes in veterans with unilateral nontraumatic transtibial amputation (TTA). METHODS This will be a 3-arm, parallel, assessor-blinded, randomized controlled trial, with baseline, postintervention, and 3-month follow-up assessments in a VA Geriatric Research Education and Clinical Center. Participants are 54 US military veterans ranging in age from 50 to 85 years with a unilateral transtibial nontraumatic amputation. Participants will be randomized into 1 of 3 groups: error-augmentation training (EAT), error-correction training (ECT), or supervised walking (CTL). Each group will complete 8 split-belt treadmill walking training sessions of 25 minutes each over 4 weeks. The EAT group will walk with belts moving at asymmetrical speeds. The ECT group will walk to the cadence of a metronome and the split belts moving at symmetrical speeds. The CTL group will walk with symmetrical belt speeds and without feedback. Step length symmetry is the primary outcome and will be assessed using an asymmetry index during overground walking. Secondary outcomes include lower extremity joint work during treadmill walking, 6-Minute Walk Test performance, daily step count, participant-perceived disability, and residual-limb integumentary health. Outcomes will be assessed at preintervention, 1-week postintervention (primary endpoint), and 13 weeks postintervention. IMPACT This study protocol focuses on an understudied area of rehabilitation for patients with nontraumatic unilateral TTA who have high levels of spatiotemporal gait asymmetry and mobility impairment. The results of this study will inform future implementation of clinical gait training interventions to improve spatiotemporal gait symmetry and long-term health and disability outcomes in patients with nontraumatic unilateral TTA.
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Affiliation(s)
- Paul W Kline
- Department of Physical Medicine and Rehabilitation, University of Colorado, Aurora, Colorado, USA
- VA Eastern Colorado Geriatric Research, Education, and Clinical Center, Rocky Mountain Regional VA Medical Center, Aurora, Colorado, USA
- Department of Physical Therapy, High Point University, High Point, North Carolina, USA
| | - Noel So
- Department of Physical Medicine and Rehabilitation, Rocky Mountain Regional VA Medical Center, Aurora, Colorado, USA
| | - Thomas Fields
- Department of Physical Medicine and Rehabilitation, Rocky Mountain Regional VA Medical Center, Aurora, Colorado, USA
| | - Elizabeth Juarez-Colunga
- VA Eastern Colorado Geriatric Research, Education, and Clinical Center, Rocky Mountain Regional VA Medical Center, Aurora, Colorado, USA
- Department of Biostatistics and Informatics, University of Colorado, Aurora, Colorado, USA
| | - Cory L Christiansen
- Department of Physical Medicine and Rehabilitation, University of Colorado, Aurora, Colorado, USA
- VA Eastern Colorado Geriatric Research, Education, and Clinical Center, Rocky Mountain Regional VA Medical Center, Aurora, Colorado, USA
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Elrod JM, Schnall BL, Mauntel TC, Watson NL, Koehler-McNicholas SR, Nickel EA, Hansen AH, Dearth CL, Hendershot BD. Biomechanical characterization of the foot-ground interaction among Service members with unilateral transtibial limb loss performing unconstrained drop-landings: Effects of drop height and added mass. J Biomech 2021; 127:110701. [PMID: 34461366 DOI: 10.1016/j.jbiomech.2021.110701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 08/12/2021] [Accepted: 08/15/2021] [Indexed: 11/29/2022]
Abstract
There exist limited data to guide the development of methodologies for evaluating impact resilience of prosthetic ankle-foot systems, particularly regarding human-device interaction in ecologically valid scenarios. The purpose of this study was to biomechanically characterize foot-ground interactions during drop-landings among Service members with and without unilateral transtibial limb loss. Seven males with, and seven males without, unilateral transtibial limb loss completed six drop-landing conditions consisting of all combinations of three heights (20 cm, 40 cm, 60 cm) and two loads (with and without a 22.2 kg weighted vest). Peak ground reaction forces (GRF), vertical GRF loading rate and impulse, as well as ankle-foot, knee, and hip joint negative (absorption) powers and work were compared across groups (i.e., contralateral side and prosthetic side vs. uninjured controls) by height and load conditions. Loading occurred primarily in the vertical direction, and increased with increasing drop height and/or with added load. Vertical GRFs were overall ~ 15% smaller on the prosthetic side (vs. controls) with similar loading rates across limbs/groups. From the most challenging condition (i.e., 60 cm with 22 kg load), ankle-foot absorption energies on the prosthetic side were 64.6 (7.2) J; corresponding values were 187.4 (8.9) J for the contralateral limb and 161.2 (6.7) J among uninjured controls. Better understanding biomechanical responses to drop-landings in ecological scenarios will help inform future iterations of mechanical testing methodologies for evaluating impact resilience of prosthetic ankle-foot systems (enhancing prescription criteria and return-to-activity considerations) as well as identifying and mitigating risk factors for long-term secondary complications within the contralateral limb (e.g., joint degeneration).
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Affiliation(s)
- Jonathan M Elrod
- Research & Development Section, Department of Rehabilitation, Walter Reed National Military Medical Center, Bethesda, MD, USA; The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, USA
| | - Barri L Schnall
- Research & Development Section, Department of Rehabilitation, Walter Reed National Military Medical Center, Bethesda, MD, USA
| | - Timothy C Mauntel
- Research & Surveillance Division, DoD-VA Extremity Trauma and Amputation Center of Excellence, Womack Army Medical Center, Fort Bragg, NC, USA; Department of Surgery, Uniformed Services University of the Health Sciences / Walter Reed National Military Medical Center, Bethesda, MD, USA
| | - Nora L Watson
- Department of Research Programs, Walter Reed National Military Medical Center, Bethesda, MD, USA
| | - Sara R Koehler-McNicholas
- Minneapolis Department of Veterans Affairs Health Care System, Minneapolis, MN, USA; Division of Rehabilitation Sciences, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Eric A Nickel
- Department of Research Programs, Walter Reed National Military Medical Center, Bethesda, MD, USA
| | - Andrew H Hansen
- Minneapolis Department of Veterans Affairs Health Care System, Minneapolis, MN, USA; Division of Rehabilitation Sciences, Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Christopher L Dearth
- Research & Surveillance Division, DoD-VA Extremity Trauma and Amputation Center of Excellence, Walter Reed National Military Medical Center, Bethesda, MD, USA; Department of Surgery, Uniformed Services University of the Health Sciences / Walter Reed National Military Medical Center, Bethesda, MD, USA
| | - Brad D Hendershot
- Research & Development Section, Department of Rehabilitation, Walter Reed National Military Medical Center, Bethesda, MD, USA; Research & Surveillance Division, DoD-VA Extremity Trauma and Amputation Center of Excellence, Walter Reed National Military Medical Center, Bethesda, MD, USA; Department of Rehabilitation Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
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Sibley AR, Strike S, Moudy SC, Tillin NA. The associations between asymmetries in quadriceps strength and gait in individuals with unilateral transtibial amputation. Gait Posture 2021; 90:267-273. [PMID: 34536691 DOI: 10.1016/j.gaitpost.2021.08.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 08/24/2021] [Accepted: 08/31/2021] [Indexed: 02/02/2023]
Abstract
BACKGROUND Individuals with unilateral transtibial amputations (ITTAs) are asymmetrical in quadriceps strength. It is unknown if this is associated with gait performance characteristics such as walking speed and limb symmetry. RESEARCH QUESTION Are quadriceps strength asymmetries related to walking speed and/ or gait asymmetries in ITTAs? METHODS Knee-extensor isometric maximum voluntary torque (MVT) and rate of torque development (RTD) were measured in eight ITTAs. Gait data were captured as the ITTAs walked at self-selected habitual and fast speeds. Step length and single support time, peak knee extension moments and their impulse and peak vertical ground reaction force (vGRF) in the braking and propulsive phases of stance were extracted. Bilateral Asymmetry Index (BAI) and, for gait variables only, difference in BAI between walking speeds (ΔBAI) were calculated. Correlation analyses assessed the relationships between MVT and RTD asymmetry and (1) walking speed; (2) gait asymmetries. RESULTS Associations between strength and gait BAIs generally became more apparent at faster walking speeds, and when the difference in BAI between fast and habitual walking speed was considered. BAI RTD was strongly negatively correlated with habitual and fast walking speeds (r=∼0.83). Larger BAI RTD was strongly correlated with propulsive vGRF BAI in fast walking, and larger ΔBAIs in vGRF during both the braking and propulsion phases of gait (r = 0.74-0.92). ITTAs who exhibited greater BAI MVT showed greater ΔBAI in single support time (r = 0.83). SIGNIFICANCE While MVT and RTD BAI appear to be associated with gait asymmetries in ITTAs, the magnitude of the asymmetry in RTD appears to be a more sensitive marker of walking speed. Based on these results, it's possible that strengthening the knee-extensors of the amputated limb to improve both MVT and RTD symmetry may benefit walking speed, and reduce asymmetrical loading in gait.
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Affiliation(s)
- Amy R Sibley
- Department of Life Sciences, Whitelands College, University of Roehampton, Holybourne Avenue, London, SW15 4JD, UK.
| | - Siobhán Strike
- Department of Life Sciences, Whitelands College, University of Roehampton, Holybourne Avenue, London, SW15 4JD, UK.
| | - Sarah C Moudy
- Department of Life Sciences, Whitelands College, University of Roehampton, Holybourne Avenue, London, SW15 4JD, UK.
| | - Neale A Tillin
- Department of Life Sciences, Whitelands College, University of Roehampton, Holybourne Avenue, London, SW15 4JD, UK.
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Davidson AM, Childers WL, Chang YH. Altering the tuning parameter settings of a commercial powered prosthetic foot to increase power during push-off may not reduce collisional work in the intact limb during gait. Prosthet Orthot Int 2021; 45:410-416. [PMID: 34469940 PMCID: PMC8487959 DOI: 10.1097/pxr.0000000000000036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 07/27/2021] [Indexed: 02/03/2023]
Abstract
BACKGROUND Increased knee osteoarthritis risk in patients with unilateral lower extremity limb loss is attributed to increased intact limb loading. Modulating powered ankle prosthesis push-off power may be an effective way to modulate intact limb loading. We examined how changes in the parameter settings of a commercial prosthetic ankle affect power delivery during push-off and the resulting collisional work experienced by the intact limb in persons with unilateral lower extremity limb loss. METHODS Five subjects with unilateral transtibial amputation were fitted with a commercially available powered ankle prosthesis (Ottobock Empower). Subjects walked on a treadmill in seven conditions, where ankle power delivery settings were adjusted using methods accessible to clinicians. Kinetics and kinematics data were collected. RESULTS Standard adjustment of parameter settings within the prosthetic foot did not alter timing of peak prosthesis power or intact limb collisional work but did have a significant effect on the magnitude of positive prosthesis ankle work. Increased prosthesis work did not decrease intact limb collisional work as predicted. CONCLUSIONS Altering the parameter settings on a commercial powered ankle prosthesis affected the magnitude, but not the timing, of power delivered. Increased prosthesis push-off power did not decrease intact limb loading.
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Affiliation(s)
- Audra M. Davidson
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA
| | | | - Young-Hui Chang
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA
- Bioengineering, Georgia Institute of Technology, Atlanta, GA
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39
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Maun JA, Gard SA, Major MJ, Takahashi KZ. Reducing stiffness of shock-absorbing pylon amplifies prosthesis energy loss and redistributes joint mechanical work during walking. J Neuroeng Rehabil 2021; 18:143. [PMID: 34548080 PMCID: PMC8456590 DOI: 10.1186/s12984-021-00939-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 09/08/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A shock-absorbing pylon (SAP) is a modular prosthetic component designed to attenuate impact forces, which unlike traditional pylons that are rigid, can compress to absorb, return, or dissipate energy. Previous studies found that walking with a SAP improved lower-limb prosthesis users' comfort and residual limb pain. While longitudinal stiffness of a SAP has been shown to affect gait kinematics, kinetics, and work done by the entire lower limb, the energetic contributions from the prosthesis and the intact joints have not been examined. The purpose of this study was to determine the effects of SAP stiffness and walking speed on the mechanical work contributions of the prosthesis (i.e., all components distal to socket), knee, and hip in individuals with a transtibial amputation. METHODS Twelve participants with unilateral transtibial amputation walked overground at their customary (1.22 ± 0.18 ms-1) and fast speeds (1.53 ± 0.29 ms-1) under four different levels of SAP stiffness. Power and mechanical work profiles of the leg joints and components distal to the socket were quantified. The effects of SAP stiffness and walking speed on positive and negative work were analyzed using two-factor (stiffness and speed) repeated-measure ANOVAs (α = 0.05). RESULTS Faster walking significantly increased mechanical work from the SAP-integrated prosthesis (p < 0.001). Reducing SAP stiffness increased the magnitude of prosthesis negative work (energy absorption) during early stance (p = 0.045) by as much as 0.027 Jkg-1, without affecting the positive work (energy return) during late stance (p = 0.159), suggesting a damping effect. This energy loss was partially offset by an increase in residual hip positive work (as much as 0.012 Jkg-1) during late stance (p = 0.045). Reducing SAP stiffness also reduced the magnitude of negative work on the contralateral sound limb during early stance by 11-17% (p = 0.001). CONCLUSIONS Reducing SAP stiffness and faster walking amplified the prostheses damping effect, which redistributed the mechanical work, both in magnitude and timing, within the residual joints and sound limb. With its capacity to absorb and dissipate energy, future studies are warranted to determine whether SAPs can provide additional user benefit for locomotor tasks that require greater attenuation of impact forces (e.g., load carriage) or energy dissipation (e.g., downhill walking).
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Affiliation(s)
- Jenny Anne Maun
- Department of Biomechanics, University of Nebraska at Omaha, Omaha, NE, USA
| | - Steven A Gard
- Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.,Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA.,Jesse Brown VA Medical Center, Chicago, IL, USA
| | - Matthew J Major
- Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.,Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA.,Jesse Brown VA Medical Center, Chicago, IL, USA
| | - Kota Z Takahashi
- Department of Biomechanics, University of Nebraska at Omaha, Omaha, NE, USA.
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40
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van der Zee TJ, Kuo AD. Soft tissue deformations explain most of the mechanical work variations of human walking. J Exp Biol 2021; 224:272226. [PMID: 34387332 DOI: 10.1242/jeb.239889] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 08/10/2021] [Indexed: 11/20/2022]
Abstract
Humans perform mechanical work during walking, some by leg joints actuated by muscles, and some by passive, dissipative soft tissues. Dissipative losses must be restored by active muscle work, potentially in amounts sufficient to cost substantial metabolic energy. The most dissipative, and therefore costly, walking conditions might be predictable from the pendulum-like dynamics of the legs. If this behavior is systematic, it may also predict the work distribution between active joints and passive soft tissues. We therefore tested whether the overall negative work of walking, and the fraction due to soft tissue dissipation, are both predictable by a simple dynamic walking model across a wide range of conditions. The model predicts whole-body negative work from the leading leg's impact with ground (termed the Collision), to increase with the squared product of walking speed and step length. We experimentally tested this in humans (N=9) walking in 26 different combinations of speed (0.7 - 2.0 m·s-1) and step length (0.5 - 1.1 m), with recorded motions and ground reaction forces. Whole-body negative Collision work increased as predicted (R2=0.73), with a consistent fraction of about 63% (R2=0.88) due to soft tissues. Soft tissue dissipation consistently accounted for about 56% of the variation in total whole-body negative work, across a wide range of speed and step length combinations. During typical walking, active work to restore dissipative losses could account for 31% of the net metabolic cost. Soft tissue dissipation, not included in most biomechanical studies, explains most of the variation in negative work of walking, and could account for a substantial fraction of the metabolic cost.
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Affiliation(s)
- Tim J van der Zee
- University of Calgary, Faculty of Kinesiology, Biomedical Engineering Graduate Program, Calgary, AB, T2N 1N4, Canada
| | - Arthur D Kuo
- University of Calgary, Faculty of Kinesiology, Biomedical Engineering Graduate Program, Calgary, AB, T2N 1N4, Canada
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41
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Smith RE, Lichtwark GA, Kelly LA. The energetic function of the human foot and its muscles during accelerations and decelerations. J Exp Biol 2021; 224:268322. [PMID: 34018550 DOI: 10.1242/jeb.242263] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 05/13/2021] [Indexed: 11/20/2022]
Abstract
The human foot is known to aid propulsion by storing and returning elastic energy during steady-state locomotion. While its function during other tasks is less clear, recent evidence suggests the foot and its intrinsic muscles can also generate or dissipate energy based on the energetic requirements of the center of mass during non-steady-state locomotion. In order to examine contributions of the foot and its muscles to non-steady-state locomotion, we compared the energetics of the foot and ankle joint while jumping and landing before and after the application of a tibial nerve block. Under normal conditions, energetic contributions of the foot rose as work demands increased, while the relative contributions of the foot to center of mass work remained constant with increasing work demands. Under the nerve block, foot contributions to both jumping and landing decreased. Additionally, ankle contributions were also decreased under the influence of the block for both tasks. Our results reinforce findings that foot and ankle function mirror the energetic requirements of the center of mass and provide novel evidence that foot contributions remain relatively constant under increasing energetic demands. Also, while the intrinsic muscles can modulate the energetic capacity of the foot, their removal accounted for only a 3% decrement in total center of mass work. Therefore, the small size of intrinsic muscles appears to limit their capacity to contribute to center of mass work. However, their role in contributing to ankle work capacity is likely important for the energetics of movement.
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Affiliation(s)
- Ross E Smith
- School of Human Movement and Nutrition Sciences , The University of Queensland, Brisbane, QLD 4072, Australia
| | - Glen A Lichtwark
- School of Human Movement and Nutrition Sciences , The University of Queensland, Brisbane, QLD 4072, Australia
| | - Luke A Kelly
- School of Human Movement and Nutrition Sciences , The University of Queensland, Brisbane, QLD 4072, Australia
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42
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Kaufman KR, Bernhardt K. Functional performance differences between carbon fiber and fiberglass prosthetic feet. Prosthet Orthot Int 2021; 45:205-213. [PMID: 33856155 DOI: 10.1097/pxr.0000000000000004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 11/16/2020] [Indexed: 02/03/2023]
Abstract
BACKGROUND Persons with lower limb amputation require increased functionality. The largest category of feet for active individuals with a transtibial amputation is energy storage and return (ESR) feet. These feet are typically constructed of carbon fiber composite materials. Recently, a prosthetic foot composed of a fiberglass composite has emerged in the market. However, there are no comparative studies of these devices. OBJECTIVES Compare the biomechanical performance and prosthesis-related quality of life when using a fiberglass prosthetic foot design compared with traditional carbon fiber ESR designs. STUDY DESIGN This is a repeated-measures randomized cross-over trial. METHODS Gait analysis was performed on 10 experienced male subjects with unilateral transtibial amputations (K-level III) while walking on level ground and a ramp. Patient-reported outcomes were collected using the Prosthesis Evaluation Questionnaire. RESULTS Gait data demonstrated increased ankle dorsiflexion (P < .01), similar ankle moments (P = .07), and increased ankle power generation (P = .01) when using the fiberglass foot. The increased power generation occurred at the correct time in the gait cycle such that the timing and magnitude of peak knee flexion was unaffected (P > .19). The fiberglass foot had greater energy absorption during gait (P = .01) with no difference in energy return (P = .37). The subjects expressed improved prosthesis-related quality of life with the fiberglass foot (P = .01). CONCLUSIONS The findings of this study demonstrate that the new ESR foot comprising a fiberglass material had better performance than traditional designs using a carbon fiber material.
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Affiliation(s)
- Kenton R Kaufman
- Motion Analysis Laboratory, Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN
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43
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Articular Cartilage Friction, Strain, and Viability Under Physiological to Pathological Benchtop Sliding Conditions. Cell Mol Bioeng 2021; 14:349-363. [PMID: 34295444 DOI: 10.1007/s12195-021-00671-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/06/2021] [Indexed: 10/21/2022] Open
Abstract
In vivo, articular cartilage is exceptionally resistant to wear, damage, and dysfunction. However, replicating cartilage's phenomenal in vivo tribomechanics (i.e., high fluid load support, low frictions and strains) and mechanobiology on the benchtop has been difficult, because classical testing approaches tend to minimize hydrodynamic contributors to tissue function. Our convergent stationary contact area (cSCA) configuration retains the ability for hydrodynamically-mediated processes to contribute to interstitial hydration recovery and tribomechanical function via 'tribological rehydration'. Using the cSCA, we investigated how in situ chondrocyte survival is impacted by the presence of tribological rehydration during the reciprocal sliding of a glass counterface against a compressively loaded equine cSCA cartilage explant. When tribological rehydration was compromised during testing, by slow-speed sliding, 'pathophysiological' tribomechanical environments and high surface cell death were observed. When tribological rehydration was preserved, by high-speed sliding, 'semi-physiological' sliding environments and suppressed cell death were realized. Inclusion of synovial fluid during testing fostered 'truly physiological' sliding outcomes consistent with the in vivo environment but had limited influence on cell death compared to high-speed sliding in PBS. Subsequently, path analysis identified friction as a primary driver of cell death, with strain an indirect driver, supporting the contention that articulation mediated rehydration can benefit both the biomechanical properties and biological homeostasis of cartilage. Supplementary Information The online version contains supplementary material available at 10.1007/s12195-021-00671-2.
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44
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Ding Z, Jarvis HL, Bennett AN, Baker R, Bull AMJ. Higher knee contact forces might underlie increased osteoarthritis rates in high functioning amputees: A pilot study. J Orthop Res 2021; 39:850-860. [PMID: 32427347 DOI: 10.1002/jor.24751] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 04/24/2020] [Accepted: 05/01/2020] [Indexed: 02/04/2023]
Abstract
High functioning military transtibial amputees (TTAs) with well-fitted state of the art prosthetics have gait that is indistinguishable from healthy individuals, yet they are more likely to develop knee osteoarthritis (OA) of their intact limbs. This contrasts with the information at the knees of the amputated limbs that have been shown to be at a significantly reduced risk of pain and OA. The hypothesis of this study is that biomechanics can explain the difference in knee OA risk. Eleven military unilateral TTAs and eleven matched healthy controls underwent gait analysis. Muscle forces and joint contact forces at the knee were quantified using musculoskeletal modeling, validated using electromyography measurements. Peak knee contact forces for the intact limbs on both the medial and lateral compartments were significantly greater than the healthy controls (P ≤ .006). Additionally, the intact limbs had greater peak semimembranosus (P = .001) and gastrocnemius (P ≤ .001) muscle forces compared to the controls. This study has for the first time provided robust evidence of increased force on the non-affected knees of high functioning TTAs that supports the mechanically based hypothesis to explain the documented higher risk of knee OA in this patient group. The results suggest several protentional strategies to mitigate knee OA of the intact limbs, which may include the improvements of the prosthetic foot control, socket design, and strengthening of the amputated muscles.
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Affiliation(s)
- Ziyun Ding
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Hannah L Jarvis
- Faculty of Science and Engineering, School of Healthcare Science, Manchester Metropolitan University, Manchester, United Kingdom
| | - Alexander N Bennett
- Academic Department of Military Rehabilitation, Defence Medical Rehabilitation Centre Headley Court, Epsom, United Kingdom.,National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Richard Baker
- School of Health Sciences, University of Salford, Salford, United Kingdom
| | - Anthony M J Bull
- Department of Bioengineering, Imperial College London, London, United Kingdom
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45
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Kupratis ME, Gure A, Ortved KF, Burris DL, Price C. Comparative Tribology: Articulation-induced rehydration of cartilage across species. BIOTRIBOLOGY (OXFORD) 2021; 25:100159. [PMID: 37780679 PMCID: PMC10540460 DOI: 10.1016/j.biotri.2020.100159] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Articular cartilage is a robust tissue that facilitates load distribution and wear-free articulation in diarthrodial joints. These biomechanical capabilities are fundamentally tied to tissue hydration, whereby high interstitial fluid pressures and fluid load support facilitate the maintenance of low tissue strains and frictions. Our recent ex vivo studies of cartilage sliding biomechanics using the convergent stationary contact area (cSCA) configuration, first introduced by Dowson and colleagues, unexpectedly demonstrated that sliding alone can promote recovery of interstitial pressure and lubrication lost to static compression through a mechanism termed 'tribological rehydration.' Although exclusively examined in bovine stifle cartilage to date, we hypothesized that tribological rehydration, i.e., the ability to recover/modulate tissue strains and lubrication through sliding, is a universal behavior of articular cartilage. This study aimed to establish if, and to what extent, sliding-induced tribological rehydration is conserved in articular cartilage across a number of preclinical animal species/models and diarthrodial joints. Using a comparative approach, we found that articular cartilage from equine, bovine, ovine, and caprine stifles, and porcine stifle, hip, and tarsal joints all exhibited remarkably consistent sliding speed-dependent compression/strain recovery and lubrication behaviors under matched contact stresses (0.25 MPa). All cartilage specimens tested supported robust, tribological rehydration during high-speed sliding (>30 mm/s), which as a result of competitive recovery of interstitial lubrication, promoted remarkable decreases in kinetic friction during continuous sliding. The conservation of tribological rehydration across mammalian quadruped articular cartilage suggests that sliding-induced recovery of interstitial hydration represents an important tissue adaptation and largely understudied contributor to the biomechanics of cartilage and joints.
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Affiliation(s)
| | - Ahmed Gure
- Bioengineering, University of Texas Arlington
| | - Kyla F. Ortved
- Clinical Studies, New Bolton Center, University of Pennsylvania
| | - David L. Burris
- Biomedical Engineering, University of Delaware
- Mechanical Engineering, University of Delaware
| | - Christopher Price
- Biomedical Engineering, University of Delaware
- Mechanical Engineering, University of Delaware
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46
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Birch JV, Kelly LA, Cresswell AG, Dixon SJ, Farris DJ. Neuromechanical adaptations of foot function to changes in surface stiffness during hopping. J Appl Physiol (1985) 2021; 130:1196-1204. [PMID: 33571058 DOI: 10.1152/japplphysiol.00401.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Humans choose work-minimizing movement strategies when interacting with compliant surfaces. Our ankles are credited with stiffening our lower limbs and maintaining the excursion of our body's center of mass on a range of surface stiffnesses. We may also be able to stiffen our feet through an active contribution from our plantar intrinsic muscles (PIMs) on such surfaces. However, traditional modeling of the ankle joint has masked this contribution. We compared foot and ankle mechanics and muscle activation on low, medium, and high stiffness surfaces during bilateral hopping using a traditional and anatomical ankle model. The traditional ankle model overestimated work and underestimated stiffness compared with the anatomical model. Hopping on a low stiffness surface resulted in less longitudinal arch compression with respect to the high stiffness surface. However, because midfoot torque was also reduced, midfoot stiffness remained unchanged. We observed lower activation of the PIMs, soleus, and tibialis anterior on the low and medium stiffness conditions, which paralleled the pattern we saw in the work performed by the foot and ankle. Rather than performing unnecessary work, participants altered their landing posture to harness the energy stored by the sprung surface in the low and medium conditions. These findings highlight our preference to minimize mechanical work when transitioning to compliant surfaces and highlight the importance of considering the foot as an active, multiarticular, part of the human leg.NEW & NOTEWORTHY When seeking to understand how humans adapt their movement to changes in substrate, the role of the human foot has been neglected. Using multi-segment foot modeling, we highlight the importance of adaptable foot mechanics in adjusting to surfaces of different compliance. We also show, via electromyography, that the adaptations are under active muscular control.
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Affiliation(s)
- Jonathon V Birch
- Sport & Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom.,School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Luke A Kelly
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Andrew G Cresswell
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Sharon J Dixon
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Dominic J Farris
- Sport & Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom.,School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Queensland, Australia
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47
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McDonald KA, Teater RH, Cruz JP, Kerr JT, Bastas G, Zelik KE. Adding a toe joint to a prosthesis: walking biomechanics, energetics, and preference of individuals with unilateral below-knee limb loss. Sci Rep 2021; 11:1924. [PMID: 33479374 PMCID: PMC7820350 DOI: 10.1038/s41598-021-81565-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 12/21/2020] [Indexed: 11/15/2022] Open
Abstract
Toe joints play an important functional role in able-bodied walking; however, for prosthesis users, the effect of adding a toe joint to a passive prosthetic foot remains largely unknown. The current study explores the kinematics, kinetics, rate of oxygen consumption and user preference of nine individuals with below-knee limb loss. Participants walked on a passive prosthetic foot in two configurations: with a Flexible, articulating toe joint and with a Locked-out toe joint. During level treadmill gait, participants exhibited a decrease in Push-Off work when using the Flexible toe joint prosthesis versus the Locked toe joint prosthesis: 16% less from the prosthesis (p = 0.004) and 10% less at the center of mass level (p = 0.039). However, between configurations, participants exhibited little change in other gait kinematics or kinetics, and no apparent or consistent difference in the rate of oxygen consumption (p = 0.097). None of the traditional biomechanical or metabolic outcomes seemed to explain user preference. However, an unexpected and intriguing observation was that all participants who wore the prosthesis on their dominant limb preferred the Flexible toe joint, and every other participant preferred the Locked configuration. Although perhaps coincidental, such findings may suggest a potential link between user preference and limb dominance, offering an interesting avenue for future research.
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Affiliation(s)
- Kirsty A McDonald
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37212, USA.
- Department of Exercise Physiology, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Rachel H Teater
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37212, USA
| | - Justin P Cruz
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37212, USA
| | - John T Kerr
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37212, USA
| | - Gerasimos Bastas
- Department of Physical Medicine and Rehabilitation, Vanderbilt University, Nashville, TN, 37212, USA
| | - Karl E Zelik
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37212, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37212, USA
- Department of Physical Medicine and Rehabilitation, Vanderbilt University, Nashville, TN, 37212, USA
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48
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Gonzalez AE, Pineda Gutierrez A, Kern AM, Takahashi KZ. Association between foot thermal responses and shear forces during turning gait in young adults. PeerJ 2021; 9:e10515. [PMID: 33552710 PMCID: PMC7819117 DOI: 10.7717/peerj.10515] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 11/17/2020] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The human foot typically changes temperature between pre and post-locomotion activities. However, the mechanisms responsible for temperature changes within the foot are currently unclear. Prior studies indicate that shear forces may increase foot temperature during locomotion. Here, we examined the shear-temperature relationship using turning gait with varying radii to manipulate magnitudes of shear onto the foot. METHODS Healthy adult participants (N = 18) walked barefoot on their toes for 5 minutes at a speed of 1.0 m s-1 at three different radii (1.0, 1.5, and 2.0 m). Toe-walking was utilized so that a standard force plate could measure shear localized to the forefoot. A thermal imaging camera was used to quantify the temperature changes from pre to post toe-walking (ΔT), including the entire foot and forefoot regions on the external limb (limb farther from the center of the curved path) and internal limb. RESULTS We found that shear impulse was positively associated with ΔT within the entire foot (P < 0.001) and forefoot (P < 0.001): specifically, for every unit increase in shear, the temperature of the entire foot and forefoot increased by 0.11 and 0.17 °C, respectively. While ΔT, on average, decreased following the toe-walking trials (i.e., became colder), a significant change in ΔT was observed between radii conditions and between external versus internal limbs. In particular, ΔT was greater (i.e., less negative) when walking at smaller radii (P < 0.01) and was greater on the external limb (P < 0.01) in both the entire foot and forefoot regions, which were likely explained by greater shear forces with smaller radii (P < 0.0001) and on the external limb (P < 0.0001). Altogether, our results support the relationship between shear and foot temperature responses. These findings may motivate studying turning gait in the future to quantify the relationship between shear and foot temperature in individuals who are susceptible to abnormal thermoregulation.
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Affiliation(s)
- Angel E. Gonzalez
- Department of Biomechanics, University of Nebraska—Omaha, Omaha, NE, United States of America
| | - Ana Pineda Gutierrez
- Department of Biomechanics, University of Nebraska—Omaha, Omaha, NE, United States of America
| | - Andrew M. Kern
- Department of Biomechanics, University of Nebraska—Omaha, Omaha, NE, United States of America
| | - Kota Z. Takahashi
- Department of Biomechanics, University of Nebraska—Omaha, Omaha, NE, United States of America
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Effects of age and speed on the ankle-foot system's power during walking. Sci Rep 2020; 10:14903. [PMID: 32913325 PMCID: PMC7484792 DOI: 10.1038/s41598-020-71763-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 07/31/2020] [Indexed: 11/08/2022] Open
Abstract
Structural and functional changes in the foot have been associated with age-related changes in gait mechanics, but walking speed may be a confounding factor in this relationship. The aim of this study was to investigate the effect of aging and speed on the ankle-foot power output during level walking. The effects of speed and aging on features of the mechanical power and work of the ankle and foot were quantified with a gait analysis of 24 young and 16 older individuals walking at different speeds. We observed gait speed having a significant effect on all the investigated features: peak power and positive and negative work of the ankle, foot, and sum of the ankle and foot (average effect size: 0.64 ± 0.22, from 0.26 to 0.87). We observed age having no effect on these same features (average effect size: 0.23 ± 0.12, from 0.03 to 0.39), with the exception of age's effect when combined with speed on the negative work of the foot. We performed additional analysis to illustrate how the speed can become a confounding factor to the understanding of the age effect on the gait biomechanics. Based on the influence of gait speed on the mechanical power of the ankle-foot system, it is essential that studies control for the effect of gait speed if there is interest in understanding age-related effects, particularly when studying frail older individuals.
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Schmitthenner D, Sweeny C, Du J, Martin AE. The Effect of Stiff Foot Plate Length on Walking Gait Mechanics. J Biomech Eng 2020; 142:091012. [PMID: 32280960 DOI: 10.1115/1.4046882] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Indexed: 11/08/2022]
Abstract
Exoskeletons are increasingly being used to treat gait pathologies. Many of these exoskeletons use a foot plate to actuate the foot, altering the effective stiffness of the foot. Stiffness of the biological foot and ankle plays an important role in the energy modulating function of the leg, so it is important to examine how a foot plate in and of itself impacts gait. Therefore, this study quantified how foot plates themselves alter the walking gait of 16 healthy young adults. The effect of the foot plate length was also examined through the use of two foot plates, one that ended at the metatarsals and one that extended past the toes, about 20% longer. Gait parameters examined included walking speed, step frequency, joint angles for the hip, knee, ankle, forefoot, and toe, ground reaction forces (GRF), and foot-ankle power. The most significant changes were caused by the full plate, which caused an average 13% decrease in the ankle range of motion (ROM) and a 23% decrease in forward GRF at push off. The shorter plate also decreased ankle ROM to a lesser degree. This indicates that the presence of a foot plate impacted foot and ankle kinematics. However, the presence of the tested foot plate had no effect on walking speed or hip or knee kinematics. This indicates that subjects were mostly able to compensate both kinematically and energetically via their foot and ankle for the increased foot stiffness due to the tested foot plate.
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Affiliation(s)
- Dave Schmitthenner
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, PA 16802
| | - Carolyn Sweeny
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, PA 16802
| | - Jing Du
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, PA 16802
| | - Anne E Martin
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, PA 16802
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