Taking a load off during training may help volleyball players jump higher, according to Australian research published in the January issue of the Journal of Science & Medicine in Sport.
Assisted jump training, in which 10 kg of assistance was provided by a bungee system, was associated with significantly higher scores on two jumping tests after five weeks than conventional jump training.
Researchers from the Queensland Academy of Sport in Nathan, Australia, analyzed seven male junior-national team members in the cross-over study, in which each subject participated in both five-week training programs, with a three-week washout period in between. Training involved three sessions per week of countermovement vertical jump training, with or without assistance.
The assisted training was associated with significant increases in countermovement vertical jump height and spike jump height, corresponding to effect sizes of 1.22 and 1.31, respectively. Conventional training did not significantly affect either jump height outcome.
The authors hypothesized that the assisted technique improves jump height by facilitating more rapid shortening in the leg extensor muscles.