Bishop, D., Jenkins, D. G., MacKinnon, L. T., McEniery, M., & Carey, M. F. (1999). The effects of strength training on endurance performance and muscle characteristics. Medicine and Science in Sports and Exercise, 31, 886-891.

The purpose of this study was to determine the effects of resistance training on endurance performance and selected muscle characteristics of female cyclists.

Endurance-trained, female cyclists, (N = 21; aged 18-42), were randomly assigned to either a resistance training (RT; N = 14) or a control group (CON; N = 7). Resistance training (twice per week) consisted of five sets to failure (2-8 RM) of parallel squats for 12 weeks. Ss were tested before and immediately after the resistance-training period. Ss completed an incremental cycle test to determine both lactate threshold (LT) and peak oxygen consumption (VO2). Endurance performance was assessed by average power output during a 1-hour cycle test (OHT). Leg strength was determined as each S's 1 RM concentric squat. Resting muscle was sampled by needle biopsy from the vastus lateralis muscle and analyzed for fiber type diameter, fiber type percentage, and the activities of 2-oxoglutarate dehydrogenase and phosphofructokinase enzymes.

After the resistance training program, there was a significant increase in 1 RM concentric squat strength for RT (35.9%) but not for CON (3.7%). However, there were no significant changes in OHT performance, LT, VO2, muscle fiber characteristics, or enzyme activities in either group.

Implication. Increased leg strength does not improve cycle endurance performance in endurance-trained, female cyclists.

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