INFLUENCE OF 2 DIFFERENT MODES OF RESISTANCE TRAINING IN FEMALE SUBJECTS

In resistance training, it has been empirically accepted that muscle h ypertrophy is developed by low intensity and high volume training, whi le muscle strength and power are developed by high intensity and low v olume training. The purpose of the present study was to investigate th e influence of two different modes of resistance training on isokineti c strength and muscle cross-sectional area (CSA) in females. Eleven fe males, who had no experience in resistance training, participated in t his study and were randomly divided into two groups. The former consis ted of 4-5 sets of 15-20 RM (repetition maximum) with sufficient rest between sets (Group H), while the latter consisted of 8-9 sets of 4-6 RM with 90 s of rest between sets (Group S). The former was assumed to be appropriate for muscle hypertrophy and the latter muscle strength, respectively. All subjects completed isotonic knee extension exercise three times a week for 8 weeks. Measurements were made on quadriceps muscle cross-sectional area (CSA) and isokinetic torques at 0, 60, 180 , and 300 degrees/s before training, at the fifth week and the end of training period. Muscle CSA was defined as the sum of CSA measured at 30, 50 and 70% of femur length, After training, muscle CSA had signifi cantly increased in both groups : 3.3 +/- 0.7% (p < .05) for group H a nd 3.6 +/- 1.1% (p < .05) for group S, respectively. While the changes in isokinetic torque were 43.4 +/- 47.5% (p < .05) for group H and 27 .4 +/ 31.3% (p < .05) for group S, respectively. In both groups the pe rcentage changes of the isokinetic strength were significantly higher than those of the CSA. No significant difference in these variables we re found between the two groups. These results suggest that during the early phase of resistance training two different modes of resistance training may have similar effects on muscle CSA and isokinetic strengt h in untrained females.