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Hypertrophy, Resistance Training, and the Nature of Skeletal Muscle Activation

Ruther Christine L.; Golden, Catherine L.; Harris, Robert T.; Dudley, Gary A.
The Journal of Strength & Conditioning Research: August 1995
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ABSTRACTThis study compared hypertrophy of the left quadriceps femoris (QF) after sedentary subjects trained 2 days a week for 9 weeks using electrical stimulation or voluntary effort. Each day, 3 to 5 sets of 10 lengthening and shortening actions were performed. Maximal effort was used for voluntary training. Electrical stimulation evoked tetanic force in 50% or more of the QF. Muscle cross-sectional area, determined by MR imaging, showed a group × time × leg interaction (p < 0.05). This reflected a 10% increase for the left QF with electrical stimulation as compared to the 4% increase after voluntary training. The right, untrained QF did not change in size (p > 0.05) after either intervention. Voluntary and electrical stimulation trainees, respectively, showed 25 and 56% increases (p < 0.05) in training torque. The results suggest that voluntary effort limits hypertrophy early in resistance training, as done in this study.

This study compared hypertrophy of the left quadriceps femoris (QF) after sedentary subjects trained 2 days a week for 9 weeks using electrical stimulation or voluntary effort. Each day, 3 to 5 sets of 10 lengthening and shortening actions were performed. Maximal effort was used for voluntary training. Electrical stimulation evoked tetanic force in 50% or more of the QF. Muscle cross-sectional area, determined by MR imaging, showed a group × time × leg interaction (p < 0.05). This reflected a 10% increase for the left QF with electrical stimulation as compared to the 4% increase after voluntary training. The right, untrained QF did not change in size (p > 0.05) after either intervention. Voluntary and electrical stimulation trainees, respectively, showed 25 and 56% increases (p < 0.05) in training torque. The results suggest that voluntary effort limits hypertrophy early in resistance training, as done in this study.

© 1995 National Strength and Conditioning Association