the literature presents contradictory statements concerning the effectiveness of free weights, isokinetic devices and plyometric exercises on the development of lower extremity power, and lean body mass {coyle, feiring, rotkis, cote, roby, lee, & wilmore, 1981; gettman, cutler & strathman, 1980; pipes & wilmore, 1975; promoli & holt, 1979; verhoshanski & tatyan, 1983; and scoles, 1978) . there is limited evidence in the literature measuring the effectiveness of combining plyometrics and various alternative resistance training devices. the training effects of four experimental groups were investigated; free weights (fw), hydra-fitness (hf), hydra- fitness plus plyometrics (hfp), and free weights plus plyometrics (fwp). pre-training and post-training tests for the lower extremity measured lean body mass, muscular peak power at slow and fast speeds (60, and 180 degrees/second), powerendurance and vertical jump power. forty physical education 世界杯2022赛程表淘汰赛 were randomly assigned into four groups; free weights, hydra-fitness, hydra-fitness plus plyometrics, and free weights plus plyometrics. the intensity of each group was equated. subjects were trained three times per week for seven weeks. a 4 (groups) by 2 (tests) anova with repeated measures on the last factor (p<.05) was employed on pre and post training raw data. post-hoc technique (scheffe' method) was employed when significant interactions were found. all groups improved the lean body mass, vertical jump, and power-endurance after training. there were no significant differences found between the four training groups. plyometrics in combination with free weights or hydra-fitness appear to have a positive training effect on power.