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Updated: Apr 3, 2026

Muscle Imbalances: Testing and Training Functional Eccentric Hamstring Strength in Athletic Populations
Published on: May 1, 2018
Muscle activation of the quadriceps and hamstrings during incremental running
Clayton L Camic1, Attila J Kovacs1, Evan A Enquist2
1Human Performance Laboratory, Exercise and Sport Science, University of Wisconsin-La Crosse, La Crosse, Wisconsin, 54601, USA.
Introduction:
The aim of this study was to determine the patterns of responses for the electromyographic (EMG) amplitude vs. oxygen uptake ( V̇O2 ) relationships from muscles of the quadriceps femoris and hamstrings during incremental treadmill running.
Methods:
Twelve men volunteered to perform an incremental test to exhaustion while EMG signals were recorded from the vastus lateralis, vastus medialis, biceps femoris, and semitendinosus muscles. Polynomial regression analyses were used to determine the best model fit for the EMG amplitude vs. V̇O2 relationships.
Results:
There were significant (P < 0.05) increases in EMG amplitude across V̇O2 for the vastus lateralis (quadratic, R = 0.995), vastus medialis (quadratic, R = 0.997), biceps femoris (cubic, R = 0.999), and semitendinosus (linear, R = 0.992) muscles as well as the hamstrings-to-quadriceps ratio (cubic, R = 0.999).
Conclusion:
These findings indicate that the patterns of responses for muscle activation vs. exercise intensity appear to be unique among muscles of the thigh.
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