Introduction: According to recent works concerning positive effects of resistance training and plyometric training on strength and body composition, it seems combination of both training methods might be an effective way to improve muscular strength and body composition simultaneously. Hence, the purpose of this study was to investigate the effects of resistance and plyometric training, and combination of which on maximal strength, body composition and body mass index.
Methodology: Fourteen active females (age: 28.1±3.4 years, height: 164±5 cm, body mass: 65.6±6.7 kg) were randomly divided into 4 groups. RT (n=10) performed resistance training three times per week for 12 weeks. PT (n=10) performed plyometric training three times per week for 12 weeks. RT+PT (n=10) performed combined resistance and plyometric training three times per week for 12 weeks. And CON (n=10) performed their normal training through 12 weeks. Pretest and posttest were 1 repetition maximum (1RM) leg press, leg squat, knee extension and flexion. As well, body composition assessed by bioelectrical impedance analysis
Results: Significant improvements (p<0.05) were found in 1RM leg press (RT=+8.7%, RT+PR=13.2%), 1RM leg squat (RT=13.3%, PT=+7.2%, RT+PT=+19.7%, CON=+7.6%), knee extension (RT=+8.2%, RT+PT=+11.3%), knee flexion (RT=+16.9%, PT=+9.1%, RT+PT= +21.6%), fat percentage (PT= -6.1%, RT+PT=-13.6%) and body mass index (RT=+2.5%). Improvement in 1RM leg press and knee flexion in RT+PT was significantly greater than improvement in group CON. Changes in 1RM leg squat in group RT+PT was significantly greater than PT and group CON. Also, decrease in fat percentage was significantly greater in RT+PT compared to group CON.
Discussion: A period of RT, PT and RT+PT may improve muscular strength through enhancement of rate of force development and neuromuscular function, may decrease fat percentage through increase in metabolism as consequence of muscular hypertrophy, and may enhance BMI mediated by muscular hypertrophy. Although all three training methods could be effective to improve muscular strength, combined method may be more effective than PT and RT in enhancement of strength and body composition profile.