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Harry JR, Simms A, Hite M. Establishing Phase Definitions for Jump and Drop Landings and an Exploratory Assessment of Performance-Related Metrics to Monitor During Testing. J Strength Cond Res 2024; 38:e62-e71. [PMID: 38090985 DOI: 10.1519/jsc.0000000000004700] [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: 01/24/2024]
Abstract
ABSTRACT Harry, JR, Simms, A, and Hite, M. Establishing phase definitions for jump and drop landings and an exploratory assessment of performance-related metrics to monitor during testing. J Strength Cond Res 38(2): e62-e71, 2024-Landing is a common task performed in research, physical training, and competitive sporting scenarios. However, few have attempted to explore landing mechanics beyond its hypothesized link to injury potential, which ignores the key performance qualities that contribute to performance, or how quickly a landing can be completed. This is because a lack of (a) established landing phases from which important performance and injury risk metrics can be extracted and (b) metrics known to have a correlation with performance. As such, this article had 2 purposes. The first purpose was to use force platform data to identify easily extractable and understandable landing phases that contain metrics linked to both task performance and overuse injury potential. The second purpose was to explore performance-related metrics to monitor during testing. Both purposes were pursued using force platform data for the landing portion of 270 jump-landing trials performed by a sample of 14 NCAA Division 1 men's basketball players (1.98 ± 0.07 m; 94.73 ± 8.01 kg). The proposed phases can separate both jump-landing and drop-landing tasks into loading, attenuation, and control phases that consider the way vertical ground reaction force (GRF) is purposefully manipulated by the athlete, which current phase definitions fail to consider. For the second purpose, Pearson's correlation coefficients, the corresponding statistical probabilities ( α = 0.05), and a standardized strength interpretation scale for correlation coefficients (0 < trivial ≤ 0.1 < small ≤ 0.3 < moderate ≤ 0.5 < large ≤ 0.7 < very large) were used for both the group average (i.e., all individual averages pooled together) and individual data (i.e., each individual's trials pooled together). Results revealed that landing time, attenuation phase time, average vertical GRF during landing, average vertical GRF during the attenuation phase, average vertical GRF during the control phase, vertical GRF attenuation rate, and the amortization GRF (i.e., GRF at zero velocity) significantly correlated with landing performance, defined as the ratio of landing height and landing time ( R ≥ ± 0.58; p < 0.05), such that favorable changes in those metrics were associated with better performance. This work provides practitioners with 2 abilities. First, practitioners currently assess jump capacity using jump-landing tests (e.g., countermovement jump) with an analysis strategy that makes use of landing data. Second, this work provides preliminary data to guide others when initially exploring landing test results before identifying metrics chosen for their own analysis.
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Affiliation(s)
- John R Harry
- Human Performance & Biomechanics Laboratory, Department of Kinesiology & Sport Management, Texas Tech University, Lubbock, TX
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Chun Y, McGowan CP, Seegmiller JG, Baker RT, Bailey JP. Differences in lower extremity joint stiffness during drop jump between healthy males and females. J Biomech 2023; 156:111667. [PMID: 37300979 DOI: 10.1016/j.jbiomech.2023.111667] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 05/03/2023] [Accepted: 05/24/2023] [Indexed: 06/12/2023]
Abstract
The primary purpose of this study was to examine sex differences in lower extremity joint stiffness during vertical drop jump performance. A secondary purpose was to examine the potential influence of sex on the relationship between joint stiffness and jump performance. Thirty healthy and active individuals performed 15-drop jumps from 30 and 60 cm boxes. Hip, knee, and ankle joint stiffnesses were calculated for subphases of landing using a 2nd order polynomial regression model. Males had greater hip stiffness during the loading phase in drop jumps from both box heights than females' drop jump from 60 cm box. Also, males had a greater ground reaction force at the end of eccentric phase, net jump impulse, and jump height regardless of box height. The 60 cm box height increased knee stiffness during the loading phase, but reduced hip stiffness during the loading phase and knee and ankle stiffness during the absorption phase regardless of sex. Joint stiffnesses significantly predicted drop jump height for females (p < .001, r2 = 0.579), but not for males (p = .609, r2 = -0.053). These results suggest that females may have different strategies to maximize drop jump height as compared to males.
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Affiliation(s)
- Youngmin Chun
- Department of Kinesiology, Sonoma State University, Rohnert Park, CA, USA.
| | - Craig P McGowan
- Department of Integrative Anatomical Sciences, University of Southern California, Los Angeles, CA, USA
| | - Jeffrey G Seegmiller
- Department of Movement Sciences, University of Idaho, Moscow, ID, USA; Idaho WWAMI Medical Education Program, University of Idaho, Moscow, ID, USA
| | - Russell T Baker
- Department of Movement Sciences, University of Idaho, Moscow, ID, USA; Idaho WWAMI Medical Education Program, University of Idaho, Moscow, ID, USA
| | - Joshua P Bailey
- Department of Movement Sciences, University of Idaho, Moscow, ID, USA
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Xu J, Turner A, Comfort P, Harry JR, McMahon JJ, Chavda S, Bishop C. A Systematic Review of the Different Calculation Methods for Measuring Jump Height During the Countermovement and Drop Jump Tests. Sports Med 2023; 53:1055-1072. [PMID: 36940054 PMCID: PMC10115716 DOI: 10.1007/s40279-023-01828-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/19/2023] [Indexed: 03/21/2023]
Abstract
BACKGROUND The heights obtained during the countermovement jump and drop jump tests have been measured by numerous studies using different calculation methods and pieces of equipment. However, the differences in calculation methods and equipment used have resulted in discrepancies in jump height being reported. OBJECTIVES The aim of this systematic review was to examine the available literature pertaining to the different calculation methods to estimate the jump height during the countermovement jump and drop jump. METHODS A systematic review of the literature was undertaken using the SPORTDiscus, MEDLINE, CINAHL, and PubMed electronic databases, with all articles required to meet specified criteria based on a quality scoring system. RESULTS Twenty-one articles met the inclusion criteria, relating various calculation methods and equipment employed when measuring jump height in either of these two tests. The flight time and jump-and-reach methods provide practitioners with jump height data in the shortest time, but their accuracy is affected by factors such as participant conditions or equipment sensitivity. The motion capture systems and the double integration method measure the jump height from the centre of mass height at the initial flat foot standing to the apex of jumping, where the centre of mass displacement generated by the ankle plantarflexion is known. The impulse-momentum and flight time methods could only measure the jump height from the centre of mass height at the instant of take-off to the apex of jumping, thus, providing statistically significantly lower jump height values compared with the former two methods. However, further research is warranted to investigate the reliability of each calculation method when using different equipment settings. CONCLUSIONS Our findings indicate that using the impulse-momentum method via a force platform is the most appropriate way for the jump height from the instant of take-off to the apex of jumping to be measured. Alternatively, the double integration method via a force platform is preferred to quantify the jump height from the initial flat foot standing to the apex of jumping.
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Affiliation(s)
- Jiaqing Xu
- Faculty of Science and Technology, London Sport Institute, Middlesex University, London, UK.
| | - Anthony Turner
- Faculty of Science and Technology, London Sport Institute, Middlesex University, London, UK
| | - Paul Comfort
- Directorate of Psychology and Sport, University of Salford, Salford, UK
| | - John R Harry
- Human Performance & Biomechanics Laboratory, Department of Kinesiology & Sport Management, Texas Tech University, Lubbock, TX, USA
| | - John J McMahon
- Directorate of Psychology and Sport, University of Salford, Salford, UK
| | - Shyam Chavda
- Faculty of Science and Technology, London Sport Institute, Middlesex University, London, UK
| | - Chris Bishop
- Faculty of Science and Technology, London Sport Institute, Middlesex University, London, UK
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Barker L, Siedlik J, Magrini M, Uesato S, Wang H, Sjovold A, Ewing G, Harry JR. Eccentric Force Velocity Profiling: Motor Control Strategy Considerations and Relationships to Strength and Jump Performance. J Strength Cond Res 2023; 37:574-580. [PMID: 35852373 DOI: 10.1519/jsc.0000000000004309] [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: 11/08/2022]
Abstract
ABSTRACT Barker, L, Siedlik, J, Magrini, M, Uesato, S, Wang, H, Sjovold, A, Ewing, G, and Harry, JR. . Eccentric force velocity profiling: motor control strategy considerations and relationships to strength and jump performance. J Strength Cond Res 37(3): 574-580, 2023-Currently, no studies exist on the eccentric force-velocity profile (eFVP) during drop landings from increasing drop heights, which may reveal an athlete's braking capacity and control strategies. Therefore, the purpose of this study was to assess the eFVP during bilateral drop landings from increasing drop heights. A secondary purpose was to explore and determine relevant relationships between the eFVP and common metrics like relative strength and jumping performance. Overall, 19 recreationally trained athletes from the university completed a 1-reptition maximum back squat, countermovement jumps, squat jumps, drop jumps, and drop landings from 0.3 to 1.52-m box heights in 0.15-m increments. Average force and velocity from the peak drop landing trial was used to generate an eFVP. The mean linear eFVP was -6.65x + 14.73, and the mean second order polynomial eFVP was -1.37x 2 - 25.84x + 0.17. The second-order polynomial fit the data better with large effect ( dunb = 1.05, p < 0.05). No significant correlations between the eFVP coefficients and the strength and jumping measurements were observed. Future research could investigate how training can influence the eFVP. Eccentric force production during landing may be a unique quality that requires specific development strategies, such has fast or slow eccentric training.
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Affiliation(s)
- Leland Barker
- Department of Exercise Science and Pre-Health Professions, Creighton University, Omaha, Nebraska; and
| | - Jacob Siedlik
- Department of Exercise Science and Pre-Health Professions, Creighton University, Omaha, Nebraska; and
| | - Mitchel Magrini
- Department of Exercise Science and Pre-Health Professions, Creighton University, Omaha, Nebraska; and
| | - Sarai Uesato
- Department of Exercise Science and Pre-Health Professions, Creighton University, Omaha, Nebraska; and
| | - Harvey Wang
- Department of Exercise Science and Pre-Health Professions, Creighton University, Omaha, Nebraska; and
| | - Alex Sjovold
- Department of Exercise Science and Pre-Health Professions, Creighton University, Omaha, Nebraska; and
| | - Garrett Ewing
- Department of Exercise Science and Pre-Health Professions, Creighton University, Omaha, Nebraska; and
| | - John R Harry
- Department of Kinesiology and Sport Management, Texas Tech University, Lubbock, Texas
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The Effect of Foot Position and Lean Mass on Jumping and Landing Mechanics in Collegiate Dancers. J Appl Biomech 2023; 39:15-21. [PMID: 36513075 DOI: 10.1123/jab.2021-0319] [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: 10/12/2021] [Revised: 09/26/2022] [Accepted: 10/20/2022] [Indexed: 12/15/2022]
Abstract
The purpose of this study was to investigate the effects of foot positioning and lean mass on jumping and landing mechanics in collegiate dancers. Thirteen dancers performed 3 unilateral and bilateral vertical jumps with feet in neutral and turnout positions. Dual-energy x-ray absorptiometry scans, jump height, vertical stiffness, and joint stiffness were assessed for relationships between foot positions. Jump heights were greater in right compared with left limb (P = .029) and neutral compared with turnout (P = .020) during unilateral jumping. In unilateral landing, knee stiffness was greater in turnout compared with neutral (P = .004) during the loading phase. Jump height (P < .001) was significantly increased, and vertical stiffness (P = .003) was significantly decreased during bilateral jumping in neutral compared with turnout. Significantly increased hip stiffness during the attenuation phase was observed in neutral compared with turnout (P = .006). Left-limb lean mass was significantly less than the right limb (P < .05). Adjustments for bilateral jumping were focused on hip stiffness, whereas there was a slight shift to knee strategy for unilateral jump.
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Baus J, Harry JR, Yang J. Optimization-based subject-specific planar human vertical jumping prediction: Effect of elbow flexion and weighted vest. Proc Inst Mech Eng H 2021; 236:65-71. [PMID: 34465231 DOI: 10.1177/09544119211044020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Jumping strategies differ considerably depending on athletes' physical activity demands. In general, the jumping motion is desired to have excellent performance and low injury risk. Both of these outcomes can be achieved by modifying athletes' jumping and landing mechanics. This paper presents a consecutive study on the optimization-based subject-specific planar human vertical jumping to test different loading conditions (weighted vest) during jumping with or without elbow flexion during the arm-swing based on the validated prediction model in the first part of this study. The sagittal plane skeletal model simulates the weighting, unweighting, breaking, propulsion phases and considers four loading conditions: 0%, 5%, 10%, and 15% body weight. Results show that the maximum ground reaction forces, the body center of mass position, and velocities at the take-off instant are different for different loading conditions and with/without elbow flexion. The optimization formulation is solved using MATLAB® with 35 design variables with 197 nonlinear constraints for a five-segment body model and 42 design variables with 227 nonlinear constraints for a six-segment body model. Both models are computationally efficient, and they can predict ground reaction forces, the body center of mass position, and velocity. This work is novel in the sense that presents a simulation model capable of considering different external loading conditions and the effect of elbow flexion during arm swing.
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Affiliation(s)
- Juan Baus
- Human-Centric Design Research Lab, Department of Mechanical Engineering, Texas Tech University, Lubbock, TX, USA
| | - John R Harry
- Human Performance & Biomechanics Lab, Department of Kinesiology and Sport Management, Texas Tech University, Lubbock, TX, USA
| | - James Yang
- Human-Centric Design Research Lab, Department of Mechanical Engineering, Texas Tech University, Lubbock, TX, USA
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Montalvo S, Gonzalez MP, Dietze-Hermosa MS, Eggleston JD, Dorgo S. Common Vertical Jump and Reactive Strength Index Measuring Devices: A Validity and Reliability Analysis. J Strength Cond Res 2021; 35:1234-1243. [PMID: 33629975 DOI: 10.1519/jsc.0000000000003988] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Montalvo, S, Gonzalez, MP, Dietze-Hermosa, M, Eggleston, JD, and Dorgo, S. Common vertical jump and reactive strength index measuring devices: A validity and reliability analysis. J Strength Cond Res 35(5): 1234-1243, 2021-Several field-test devices exist to assess vertical jump, but they either lack proper validation or have been validated for the countermovement jump (CMJ) only. This study aimed to quantify the validity and reliability of metrics, including jump height and the calculated reactive strength index (RSI), obtained using the flight-time method from 4 different assessment devices with 3 different vertical jump modalities in comparison to a force platform (criterion assessment). The Optojump, Push-Band 2.0, MyJump2 mobile application, and What'sMyVert mobile application were used synchronously and together with the force platforms. Thirty subjects (17 males and 13 females; age ± SD: 23.37 ± 1.87 years) performed 5 repetitions of CMJ, squat jump (SQJ), and drop jump (DJ) with a standardized 90° knee flexion for all jumps. Relative reliability was determined by intraclass correlation (ICC) and absolute reliability by coefficient of variation (CV) analyses. Excellent reliability was considered as ICC > 0.9 and CV < 10%. Validity was obtained through an ordinary least products regression, ICC, and CV. Significance was set at p < 0.05. Reliability was excellent on jump height for the CMJ (ICC ≥ 0.98; CV ≤ 8.14%) for all instruments. With the exception of the Optojump, all instruments also had excellent reliability for the SQJ (ICC ≥ 0.98; CV ≤ 6.62) and DJ (ICC ≥ 0.94; CV ≤ 8.19). For the RSI metric, all instruments had excellent relative reliability (ICC ≥ 0.92), but none had excellent absolute reliability (CV ≥ 12.5%). The MyJump2 and What'sMyVert apps showed excellent validity on all jump modalities and RSI. The Optojump and Push-Band 2.0 devices both showed system and proportional bias for several jump modalities and RSI. Overall, both mobile applications may provide coaches with a cost-effective and reliable measurement of various vertical jumps.
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Affiliation(s)
- Samuel Montalvo
- Fitness Research Facility, Department of Kinesiology, The University of Texas at El Paso, El Paso, Texas; and
| | - Matthew P Gonzalez
- Fitness Research Facility, Department of Kinesiology, The University of Texas at El Paso, El Paso, Texas; and
| | - Martin S Dietze-Hermosa
- Fitness Research Facility, Department of Kinesiology, The University of Texas at El Paso, El Paso, Texas; and
| | - Jeffrey D Eggleston
- Stanley E. Fulton Gait Research and Movement Analysis Laboratory, Department of Kinesiology, The University of Texas at El Paso, El Paso, Texas
| | - Sandor Dorgo
- Fitness Research Facility, Department of Kinesiology, The University of Texas at El Paso, El Paso, Texas; and
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Baus J, Harry JR, Yang J. Optimization-based subject-specific planar human vertical jumping prediction: Model development and validation. Proc Inst Mech Eng H 2021; 235:805-818. [PMID: 33863254 DOI: 10.1177/09544119211010924] [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] [Indexed: 11/16/2022]
Abstract
Jumping biomechanics may differ between individuals participating in various sports. Jumping motion can be divided into different phases for research purposes when seeking to understand performance, injury risk, or both. Experimental-based methods are used to study different jumping situations for their capabilities of testing other conditions intended to improve performance or further prevent injuries. External loading training is commonly used to simulate jumping performance improvement. This paper presents the optimization-based subject-specific planar human vertical jumping to develop the prediction model with and without a weighted vest and validate it through experiments. The skeletal model replicates the human motion for jumping (weighting, unweighting, breaking, propulsion) in the sagittal plane considering four different loading conditions (0% and 10% body mass): unloaded, split-loaded, front-loaded, and back-loaded. The multi-objective optimization problem is solved using MATLAB® with 35 design variables and 197 nonlinear constraints. Results show that the model is computationally efficient, and the predicted jumping motion matches the experimental data trend. The simulation model can predict vertical jumping motion and can test the effect of different loading conditions with weighted vests and arm-swing strategy on the ground reaction forces. This work is novel in the sense that it can predict ground reaction forces, joints angles, and center of mass position without any experimental data.
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Affiliation(s)
- Juan Baus
- Department of Mechanical Engineering, Human-Centric Design Research Lab, Texas Tech University, Lubbock, TX, USA
| | - John R Harry
- Department of Kinesiology and Sport Management, Human Performance & Biomechanics Lab, Texas Tech University, Lubbock, TX, USA
| | - James Yang
- Department of Mechanical Engineering, Human-Centric Design Research Lab, Texas Tech University, Lubbock, TX, USA
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Grozier CD, Cagle GK, Pantone L, Rank KB, Wilson SJ, Harry JR, Seals S, Simpson JD. Effects of medial longitudinal arch flexibility on propulsion kinetics during drop vertical jumps. J Biomech 2021; 118:110322. [PMID: 33607594 DOI: 10.1016/j.jbiomech.2021.110322] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 01/12/2021] [Accepted: 02/02/2021] [Indexed: 11/30/2022]
Abstract
This study examined the effects of medial longitudinal arch (MLA) flexibility on kinetics during the eccentric and concentric subphases of a drop vertical jump (DVJ). Physically active adults with flexible (n = 16) and stiff (n = 16) MLA completed DVJs onto a force platform from a height of 30 cm. Eccentric and concentric subphases of the DVJ were identified from the vertical ground reaction force (GRF) data. Jump height, ground contact time, reactive strength index (RSI), vertical center-of-mass depth, vertical stiffness and time of the eccentric and concentric subphases were evaluated. Amortization force, peak vertical GRF and vertical impulse were also obtained for the eccentric and concentric subphases of the DVJ. Dependent variables were compared between groups using independent samples t-tests (p < 0.05). Significantly greater vertical stiffness (p = 0.048; ES = 0.63) was found in the stiff arch group (-173.91 ± 99.73 N/kg/m) compared to the flexible arch group (-122.95 ± 63.42 N/kg/m). A moderate-magnitude difference (ES = 0.58) was observed for RSI between flexible (0.89 ± 0.39) and stiff arch (1.20 ± 0.70) groups, but was not significant (p = 0.063). The active and passive structures supporting the MLA may be used differently to achieve similar vertical jump height during a DVJ. Additional research is warranted to further understand the contributions of MLA flexibility to jumping performance.
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Affiliation(s)
- Corey D Grozier
- Department of Movement Sciences and Health, University of West Florida, Pensacola, FL, United States; Department of Kinesiology, University of North Alabama, Florence, AL, United States
| | - Gretchen K Cagle
- Department of Movement Sciences and Health, University of West Florida, Pensacola, FL, United States
| | - Lauren Pantone
- Department of Movement Sciences and Health, University of West Florida, Pensacola, FL, United States
| | - Kyle B Rank
- Department of Movement Sciences and Health, University of West Florida, Pensacola, FL, United States
| | - Samuel J Wilson
- Department of Health Sciences and Kinesiology, Georgia Southern University, Statesboro, GA, United States
| | - John R Harry
- Department of Kinesiology and Sport Management, Texas Tech University, Lubbock, TX, United States
| | - Samantha Seals
- Department of Mathematics and Statistics, University of West Florida, Pensacola, FL, United States
| | - Jeffrey D Simpson
- Department of Movement Sciences and Health, University of West Florida, Pensacola, FL, United States.
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Cohen DD, Restrepo A, Richter C, Harry JR, Franchi MV, Restrepo C, Poletto R, Taberner M. Detraining of specific neuromuscular qualities in elite footballers during COVID-19 quarantine. SCI MED FOOTBALL 2020; 5:26-31. [DOI: 10.1080/24733938.2020.1834123] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Daniel D. Cohen
- Masira Research Institute, University of Santander (UDES), Bucaramanga, Colombia
- Sports Science Center (CCD), Colombian Ministry of Sport (Mindeporte), Colombia
| | - Alfredo Restrepo
- Performance Department, América De Cali Football Club, Cali, Colombia
- Indervalle (Valle Del Cauca Institute of Sport, Physical Education and Recreation), Cali, Colombia
| | | | - John R. Harry
- Human Performance & Biomechanics Laboratory, Department of Kinesiology & Sport Management, Texas Tech University, Lubbock, TX, USA
| | | | - Carlos Restrepo
- Performance Department, América De Cali Football Club, Cali, Colombia
| | - Rodrigo Poletto
- Performance Department, América De Cali Football Club, Cali, Colombia
| | - Matt Taberner
- School of Sport and Exercise Sciences, Liverpool John Moore’s University, Liverpool, UK
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Perry SK, Buddhadev HH, Brilla LR, Suprak DN. Mechanical Demands at the Ankle Joint During Saut de Chat and Temps levé Jumps in Classically Trained Ballet Dancers. Open Access J Sports Med 2019; 10:191-197. [PMID: 31827337 PMCID: PMC6902839 DOI: 10.2147/oajsm.s234289] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 11/20/2019] [Indexed: 11/25/2022] Open
Abstract
Background During ballet, injuries to the Achilles tendon are associated with the take-off phase of various jumps. Research question The purpose of the study was to assess differences in mechanical demand on the body, specifically at the ankle, in two single-leg jumps commonly trained in ballet: a saut de chat (SDC) and a temps levé (TL). Methods Fifteen classically trained female dancers had 16 reflective markers placed on the lower body and each dancer performed each jump three times on a force plate. The marker position data and ground reaction forces (GRF) were captured synchronously at 250 Hz and 1000 Hz, respectively. Peak vertical GRF, mean rate of force development (RFD), peak ankle moment, and peak ankle power were determined and averaged across trials. Paired t-tests were used to determine differences between the SDC and the TL. Results When compared to the TL, the SDC displayed significantly higher peak vertical GRF (p = 0.003), RFD (p = 0.002), and peak ankle moment and power (p < 0.001). The effect sizes for these differences were large for all variables (Cohen’s d > 0.80). Conclusion The mechanical demand at the ankle joint is significantly greater for the SDC than the TL.
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Affiliation(s)
- Sarah K Perry
- Department of Health and Human Development, Western Washington University, Bellingham, WA, USA
| | - Harsh H Buddhadev
- Department of Health and Human Development, Western Washington University, Bellingham, WA, USA
| | - Lorraine R Brilla
- Department of Health and Human Development, Western Washington University, Bellingham, WA, USA
| | - David N Suprak
- Department of Health and Human Development, Western Washington University, Bellingham, WA, USA
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Harry JR, Lanier R, Nunley B, Blinch J. Focus of attention effects on lower extremity biomechanics during vertical jump landings. Hum Mov Sci 2019; 68:102521. [PMID: 31610993 DOI: 10.1016/j.humov.2019.102521] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 09/10/2019] [Accepted: 09/10/2019] [Indexed: 11/25/2022]
Abstract
This study examined biomechanical differences between external and internal foci of attention during vertical jump landings in males and females. Twenty-four healthy adults performed eight vertical jump landings using both internal and external foci while three-dimensional kinematic and ground reaction force (GRF) data were obtained. Two (focus) by two (sex) analyses of variance (α = 0.05) and Cohen's d effect sizes (ES) were used to compare differences in vertical GRF, joint angular positions and displacements, and lower limb joint angular work between foci and between sexes. Significantly greater knee contributions to total angular work occurred during external versus internal focus landings regardless of sex (p = .013; ES = 0.30). Significantly smaller plantarflexion angles (p = .019; ES = 0.53) and significantly greater knee flexion angles were observed at ground contact (p < .001; ES = 1.11) in males during external focus landings. Females exhibited significantly smaller knee flexion angles at both ground contact during external versus internal focus landings (p = .031; ES = 0.20) and compared to males during external focus landings (p < .001; ES = 1.76). Both peak vertical GRF (p = .003; ES = 1.54) and the ankle contributions to total angular work during loading (p = .026; ES = 1.07) were greater in females versus males regardless of foci, whereas the knee contributions to total angular work during loading were smaller in women (p = .026; ES = 1.07). Males and females might consider adopting an external focus during vertical jump landings to increase knee joint contributions to lower limb energy absorption. Females, in particular, might consider external focus use to decrease peak vertical GRF and increase the knee joint's contribution to total energy absorption to magnitudes similar to those exhibited by males.
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Affiliation(s)
- John R Harry
- Human Performance & Biomechanics Laboratory, Dept. of Kinesiology & Sport Management, Texas Tech University, 3204 Main Street, Lubbock, TX 79409, United States of America.
| | - Ryan Lanier
- Human Performance & Biomechanics Laboratory, Dept. of Kinesiology & Sport Management, Texas Tech University, 3204 Main Street, Lubbock, TX 79409, United States of America
| | - Brandon Nunley
- Human Performance & Biomechanics Laboratory, Dept. of Kinesiology & Sport Management, Texas Tech University, 3204 Main Street, Lubbock, TX 79409, United States of America
| | - Jarrod Blinch
- Motor Behavior Laboratory, Dept. of Kinesiology & Sport Management, Texas Tech University, 3204 Main Street, Lubbock, TX 79409, United States of America
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Harry JR, James CR, Dufek JS. Weighted vest effects on impact forces and joint work during vertical jump landings in men and women. Hum Mov Sci 2018; 63:156-163. [PMID: 30553141 DOI: 10.1016/j.humov.2018.12.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 12/03/2018] [Accepted: 12/08/2018] [Indexed: 10/27/2022]
Abstract
Weighted vest (WV) use during vertical jump landings (VJL) does not appear to alter peak vertical ground reaction forces (GRF) or peak joint torques. However, WV effects on joint work and sex differences during VJL are not well understood. This study assessed WV effects on vertical GRF and sagittal joint work during VJL in men and women. Twelve men and 12 women performed VJL wearing a WV with zero added mass (unloaded) and with 10% body mass (loaded) while GRF and kinematic data were obtained. Mixed-model analyses of variance (α = 0.05) and effect sizes (ES) were used to assess differences between sexes and/or load conditions. Regardless of sex, greater landing height (p < 0.001; ES = 0.37) and peak vertical GRF (p = 0.001; ES 0.51) occurred when unloaded, while greater landing time (p = 0.001; ES = 0.46) and negative lower extremity work (p < 0.001; ES = 0.41) occurred when loaded through greater negative work about the hip (p = 0.001; ES = 0.27) and ankle (p = 0.020; ES = 0.27). No differences in hip (p = 0.753; ES = 0.03), knee (p = 0.588; ES = 0.07), or ankle (p = 0.580; ES = 0.09) joint displacement were detected between loaded and unloaded conditions. Men exhibited greater landing heights (p < 0.001; ES = 2.49) and greater peak vertical GRF than women (p = 0.007; ES = 1.18), though women exhibited greater negative lower extremity work (p < 0.001; ES = 1.98) than men through greater negative knee (p < 0.001; ES = 1.98) and ankle (p = 0.032; ES = 0.94) work. No sex differences were detected for joint angular displacement about the hip (p = 0.475; ES = 0.30), knee (p = 0.666; ES = 0.18), or ankle (p = 0.084; ES = 0.71). These data revealed a unique load accommodation strategy during VJL with a WV characterized by greater lower extremity joint work performed via increased joint torque despite lesser landing height and peak vertical GRF. Women appear to perform greater lower extremity joint work than men during VJL despite lesser landing height and peak vertical GRF. Current and prospective WV users should be aware of their load accommodation strategy during VJL with an external load. Women may consider developing more refined load accommodation strategies for VJL regardless of whether external loading is applied to avoid performing excessive amounts of lower extremity work.
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Affiliation(s)
- John R Harry
- Department of Kinesiology & Sport Management, Texas Tech University, 3204 Main Street, Lubbock, TX 79409, USA.
| | - C Roger James
- Center for Rehabilitation Research, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA
| | - Janet S Dufek
- Department of Kinesiology & Nutrition Sciences, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Box 3034, Las Vegas, NV 89154, USA
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