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Lyu Y, Xie K, Shan X, Leng Y, Li L, Zhang X, Song R. Time-varying and speed-matched model for the evaluation of stroke-induced changes in ankle mechanics. J Biomech 2024; 165:111997. [PMID: 38377742 DOI: 10.1016/j.jbiomech.2024.111997] [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: 06/20/2023] [Revised: 02/09/2024] [Accepted: 02/13/2024] [Indexed: 02/22/2024]
Abstract
The ankle mechanics (stiffness and moment) are modulated continuously when interacting with the environment during human walking. However, it remains unclear how ankle mechanics vary with walking speeds, and how they are affected by stroke. This study aimed to determine time-varying ankle stiffness and moment in stroke participants during walking, comparing them with healthy participants at matched speeds. A motion capture system, surface electromyography (EMG) system and force plates were used to measure biomechanics of seven healthy participants walking at 5 controlled speeds and ten patients with stroke at self-selected speeds. The ankle moment and stiffness during the stance phase were calculated using an EMG-driven musculoskeletal model. Surface equations of ankle moment and stiffness in healthy participants, with walking speed and stance phase as variables, were proposed based on polynomial fitting. Results showed that as walking speed increased, there was an increase in the ankle stiffness and moment of healthy participants during 77 %-89 % and 63 %-91 % of stance phase, respectively. Patients with stroke had lower ankle stiffness and moment at self-selected walking speed than healthy participants at 1.04 m/s walking speed during 52 %-87 % and 52 %-91 % of stance phase, respectively. At matched walking speed, the peak values of ankle stiffness and moment in patients with stroke were significantly less than those in healthy participants (p = 0.007; p = 0.028, respectively). This study proposes a novel approach to evaluate the ankle mechanics of patients with stroke using the speed-matched model of healthy participants and may provide insights into understanding speed-dependent movement mechanisms of human walking.
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Affiliation(s)
- Yueling Lyu
- School of Biomedical Engineering, Shenzhen Campus of Sun Yat-sen University, Shenzhen 518107, China; Key Laboratory of Sensing Technology and Biomedical Instrument of Guangdong province, School of Engineering, Sun Yat-sen University, Guangzhou 510006, China
| | - Kaifan Xie
- Key Laboratory of Sensing Technology and Biomedical Instrument of Guangdong province, School of Engineering, Sun Yat-sen University, Guangzhou 510006, China
| | - Xiyao Shan
- Department of Anatomy, Aichi Medical University, Japan
| | - Yan Leng
- Department of Rehabilitation Medicine, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Le Li
- Institute of Medical Research, Northwestern Polytechnical University, Xi'an 710000, China
| | - Xianyi Zhang
- School of Biomedical Engineering, Shenzhen Campus of Sun Yat-sen University, Shenzhen 518107, China; Key Laboratory of Sensing Technology and Biomedical Instrument of Guangdong province, School of Engineering, Sun Yat-sen University, Guangzhou 510006, China.
| | - Rong Song
- School of Biomedical Engineering, Shenzhen Campus of Sun Yat-sen University, Shenzhen 518107, China; Key Laboratory of Sensing Technology and Biomedical Instrument of Guangdong province, School of Engineering, Sun Yat-sen University, Guangzhou 510006, China.
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Fang S, Vijayan V, Reissman ME, Kinney AL, Reissman T. Effects of Walking Speed and Added Mass on Hip Joint Quasi-Stiffness in Healthy Young and Middle-Aged Adults. SENSORS (BASEL, SWITZERLAND) 2023; 23:s23094517. [PMID: 37177721 PMCID: PMC10181717 DOI: 10.3390/s23094517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/30/2023] [Accepted: 05/02/2023] [Indexed: 05/15/2023]
Abstract
Joint quasi-stiffness has been often used to inform exoskeleton design. Further understanding of hip quasi-stiffness is needed to design hip exoskeletons. Of interest are wearer responses to walking speed changes with added mass of the exoskeleton. This study analyzed hip quasi-stiffness at 3 walking speed levels and 9 added mass distributions among 13 young and 16 middle-aged adults during mid-stance hip extension and late-stance hip flexion. Compared to young adults, middle-aged adults maintained a higher quasi-stiffness with a smaller range. For a faster walking speed, both age groups increased extension and flexion quasi-stiffness. With mass evenly distributed on the pelvis and thighs or biased to the pelvis, both groups maintained or increased extension quasi-stiffness. With mass biased to the thighs, middle-aged adults maintained or decreased extension quasi-stiffness while young adults increased it. Young adults decreased flexion quasi-stiffness with added mass but not in any generalizable pattern with mass amounts or distributions. Conversely, middle-aged adults maintained or decreased flexion quasi-stiffness with even distribution on the pelvis and thighs or biased to the pelvis, while no change occurred if biased to the thighs. In conclusion, these results can guide the design of a hip exoskeleton's size and mass distribution according to the intended user's age.
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Affiliation(s)
- Shanpu Fang
- Department of Mechanical and Aerospace Engineering, University of Dayton, Dayton, OH 45469, USA
| | - Vinayak Vijayan
- Department of Mechanical and Aerospace Engineering, University of Dayton, Dayton, OH 45469, USA
| | - Megan E Reissman
- Department of Mechanical and Aerospace Engineering, University of Dayton, Dayton, OH 45469, USA
| | - Allison L Kinney
- Department of Mechanical and Aerospace Engineering, University of Dayton, Dayton, OH 45469, USA
| | - Timothy Reissman
- Department of Mechanical and Aerospace Engineering, University of Dayton, Dayton, OH 45469, USA
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MacLean MK, Ferris DP. Effects of simulated reduced gravity and walking speed on ankle, knee, and hip quasi-stiffness in overground walking. PLoS One 2022; 17:e0271927. [PMID: 35944021 PMCID: PMC9362947 DOI: 10.1371/journal.pone.0271927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 07/10/2022] [Indexed: 12/04/2022] Open
Abstract
Quasi-stiffness characterizes the dynamics of a joint in specific sections of stance-phase and is used in the design of wearable devices to assist walking. We sought to investigate the effect of simulated reduced gravity and walking speed on quasi-stiffness of the hip, knee, and ankle in overground walking. 12 participants walked at 0.4, 0.8, 1.2, and 1.6 m/s in 1, 0.76, 0.54, and 0.31 gravity. We defined 11 delimiting points in stance phase (4 each for the ankle and hip, 3 for the knee) and calculated the quasi-stiffness for 4 phases for both the hip and ankle, and 2 phases for the knee. The R2 value quantified the suitability of the quasi-stiffness models. We found gravity level had a significant effect on 6 phases of quasi-stiffness, while speed significantly affected the quasi-stiffness in 5 phases. We concluded that the intrinsic muscle-tendon unit stiffness was the biggest determinant of quasi-stiffness. Speed had a significant effect on the R2 of all phases of quasi-stiffness. Slow walking (0.4 m/s) was the least accurately modelled walking speed. Our findings showed adaptions in gait strategy when relative power and strength of the joints were increased in low gravity, which has implications for prosthesis and exoskeleton design.
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Affiliation(s)
- Mhairi K. MacLean
- Department of Biomechanical Engineering, University of Twente, Enschede, The Netherlands
- * E-mail:
| | - Daniel P. Ferris
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, United States of America
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