The effects of assisted and resisted plyometric training on jump height and sprint performance among physically active females.

The aim of the present study was to compare the effects of assisted and resisted plyometric jump training on jump height, sprint performance (acceleration (0-20m), maximum speed (30-40m) and 40m sprint time) among physically active females. Fifty-six participants (age: 21.1 ± 1.7 years; body mass: 64.2 ± 7.0 kg; height: 168.0 ± 5.6 cm) were randomly allocated to either an assisted (n = 16) or resisted training group (n = 17), or a control group (n = 14). Nine participants dropped out during the intervention. The training sessions consisted of three different plyometric jump exercises over an eight-week period, while the control group continued their normal training routine. The results revealed a significant between-group difference in jump height and maximal speed. The resisted training group achieved a significantly greater improvement in jump height compared to the active control group (p = .04, ES=1.06), and a significantly greater improvement in maximal speed (p = .02, ES = 0.93) when compared to the assisted training group. No other group differences were observed for jump height, acceleration or in maximal speed (p = .31-.53). The resisted training group improved jump height (p = .01, ES = 0.62) and maximum speed (p = .03, ES = 0.48) from pre- to post-test, while the control group improved maximal speed (p = .04, ES = 0.37) and acceleration (p = .01, ES = 0.68). All three groups improved their 40m sprint time from pre- to post-test (p = .01-.04, ES = 0.38-0.45). In conclusion, resisted plyometric training was more effective than assisted plyometric training for improving the maximal speed and more effective than the active control condition for increasing jump height.

Effects of Overspeed or Overload Plyometric Training on Jump Height and Lifting Velocity.

The aim of this study was to examine the effects of overspeed or overload plyometric training on jump height and lifting velocity in resistance trained females without plyometric training experience. Fifty-six participants (age: 21.2±1.7 years; body mass: 65.1±8.2 kg; height: 168.0±5.9 cm) were randomly allocated to either an overspeed (n=18), overload (n=18), or passive control (n=16) group. The two training groups completed 18.7±1.7 sessions consisting of three different plyometric exercises with overspeed or overload over eight weeks. Apart from the external loading, the two training modalities were identical. Following the training period, the changes in the recorded variables were not significantly different from those in the control group, nor did the training groups differ from each other. The training groups improved peak and average lifting velocity in the 40 and 60% of body mass loading conditions (9.50-33.37%, p=<0.001-0.038), whereas only the average lifting velocity improved in the 80% of body mass loading condition (OS: 14.47%, p<0.001 and OL: 23.13%, p<0.001). No significant changes occurred in the control group (9.18-13.55%, P=0.062-0.980). Overspeed and overload plyometric training may be viable methods for improving lifting velocity, but not squat jump height, in a population without plyometric training experience.