Document Type
Article
Publication Date
2-2022
Publisher
Lippincott Williams & Wilkins
Source Publication
Journal of Strength and Conditioning Research
Source ISSN
1064-8011
Original Item ID
DOI: 10.1519/JSC.0000000000003874
Abstract
The purpose of this study was to determine muscle-specific contributions to lower extremity net joint moments (NJMs) during squats with different external loads. Nine healthy subjects performed sets of the back squat exercise with 0, 25, 50, and 75% of body mass as an added external load. Motion capture and force plate data were used to calculate NJMs and to estimate individual muscle forces via static optimization. Individual muscle forces were multiplied by their respective moment arms to calculate the resulting muscle-specific joint moment. Statistical parametric mapping (α = 0.05) was used to determine load-dependent changes in the time series data of NJMs and muscle-specific joint moments. Hip, knee, and ankle NJMs all increased across each load condition. The joint extension moments created by the gluteus maximus and hamstring muscles at the hip, by the vastii muscles at the knee, and by the soleus at the ankle all increased across most load conditions. Concomitantly, the flexion moment created by the hamstring muscles at the knee also increased across most load conditions. However, the ratio between joint moments created by the vastii and hamstring muscles at the knee did not change across load. Similarly, the ratio between joint moments created by the gluteus maximus and hamstring muscles at the hip did not change across load. Collectively, the results highlight how individual muscles contribute to NJMs, identify which muscles contribute to load-dependent increases in NJMs, and suggest that joint moment production among synergistic and antagonistic muscles remains constant as external load increases.
Recommended Citation
Kipp, Kristof; Kim, Hoon; and Wolf, William I., "Muscle-Specific Contributions to Lower Extremity Net Joint Moments While Squatting With Different External Loads" (2022). Exercise Science Faculty Research and Publications. 197.
https://epublications.marquette.edu/exsci_fac/197
ADA Accessible Version
Included in
Kinesiotherapy Commons, Other Rehabilitation and Therapy Commons, Physical Therapy Commons, Sports Sciences Commons
Comments
Accepted version. Journal of Strength and Conditioning Research, Vol. 36, No. 2 (February 2022): 324-331. DOI. © 2019 Lippincott Williams & Wilkins, Inc. Used with permission.