Date of Completion


Embargo Period



Resistance Training, Fat-Free Mass, Exercise, Hypertrophy

Major Advisor

William J. Kraemer, Ph.D.

Associate Advisor

Craig R. Denegar, Ph.D.

Associate Advisor

Michael F. Joseph, Ph.D.

Associate Advisor

Carl M. Maresh, Ph.D.

Associate Advisor

Jeff S. Volek, Ph.D.

Field of Study



Doctor of Philosophy

Open Access

Open Access


The hypertrophy range (8-12 repetitions at 70-85% one-repetition maximum (1RM)) has long been considered the optimal resistance training protocol for the development of fat-free mass (FFM). Recent investigations have hypothesized that lighter repetition zones (over 12 repetitions and less than 67% 1RM) are as effective as heavier loads for the development of FFM. The purpose of this investigation was to determine whether local muscular endurance workouts could sustain and further increase FFM following a program emphasizing the hypertrophy zone. Methods: Healthy, untrained subjects (36 men and 27 women, ages 23 ± 3) completed 96 resistance training workouts. After baseline testing (T1), testing of body composition (dual-energy x-ray absorptiometry (Lunar Prodigy, Madison, WI)) and performance occurred after every 32 workouts (at T2, T3, and T4). In the first block of 32 workouts, 2 of every 3 workouts emphasized the hypertrophy zone and 1/3 emphasized the strength zone (3-7 repetitions at 83 to 93% 1RM). Of the last 32 workouts, 28% of the workouts were in the hypertrophy zone, 47% in the strength zone, and 1/4 in the local muscular endurance zone. Results: FFM significantly increased from T1 (49.8 ± 10.0 kg)until T3 (52.6 ± 10.5kg), at which point it significantly decreased to T4 (52.2 ± 10.7kg). Squat strength and bone mineral density significantly increased, but vertical jump power production did not continue to increase between T3 and T4. Discussion: This investigation suggests that replacing hypertrophy-zone workouts with endurance zone workouts prevents further increases in FFM and results in a loss of FFM previously gained.