Comparison of two lower-body modes of endurance training on lower-body strength development while concurrently training.J Strength Cond Res 2009; 23(3):979-87JS
The most recent American College of Sports Medicine (1998) recommendations for quantity and quality of exercise includes both resistance and endurance exercise components. Skeletal muscle adaptations to resistance-only and endurance-only programs may be different and possibly antagonistic when both types of training are imposed concurrently. The present study examined the effect of two different modes of lower-body endurance exercise (i.e., cycle ergometry and incline treadmill walking) on lower-body strength development with concurrent resistance training designed to improve lower-body strength (i.e., bilateral leg press 1 repetition maximum [RM]). Thirty untrained participants (22 men and 8 women, ages 18-23) were randomly assigned to one of 3 training groups (resistance only [R], N = 10; resistance + cycle ergometry [RC], N = 10; and resistance + incline treadmill [RT], N = 10). The 3 training groups exercised twice per week for 9 weeks. The reduced frequency of exercise treatments were selected specifically to avoid overtraining for in-season athletes attempting to maintain offseason conditioning. Body mass and body composition measurements were taken pre- and post-training. Before training began, 3 weeks of training, 6 weeks of training, and after training, the participants also performed a 1RM test for lower-body strength. Analysis of variance comparisons with repeated measures revealed the following statistically significant changes (alpha = 0.05) in the 3 training groups over time: (a) when men and women were combined, body mass of R was significantly greater than RC and RT post-training; (b) body mass of men only was significantly greater than RC and RT post-training; (c) body composition of men only was significantly smaller for RC and RT compared with R; (d) when men and women were combined, percent change in strength revealed significantly greater gains in R compared with RT at 6 weeks; (e) when men and women were combined, percent change in strength revealed significantly greater gains in R compared with RC and RT post-training; (f) percent change in strength for men only was significantly greater for R compared with RT at 3 weeks; (g) percent change in strength for men only was significantly greater for R compared with RC and RT at 6 weeks, and RC was significantly greater than RT at 6 weeks; (h) percent change in strength in men only was significantly greater for R compared with RC and RT post-training, and RC was significantly greater than RT post-training; and (i) percent change in strength in women was significantly greater in R compared with RT post-training. The findings confirm previous studies that reported attenuated strength development with concurrent resistance and endurance training compared with resistance-only training. More importantly, this study indicates that the mode of endurance exercise in concurrent training regimens may play a role in the development of strength. Specifically, it seems that cycling is superior to treadmill endurance training for an individual with the goal of developing strength in a multijoint movement (i.e., leg press or squat) in the lower-body because it more closely mimics the biomechanical movement of these exercises.