engleski

Vertical- vs. horizontal-oriented drop-jump training: chronic effects on explosive performances of elite handball players

This study aimed to assess the chronic effects of vertical and horizontal drop-jump-based protocols on neuromuscular explosive abilities such as jumping, sprinting, and change of direction (COD). Eighteen elite male handball players (age 23.4 +/- 4.6 years ; height 192.5 +/- 3.7 cm ; weight 87.8 +/- 7.4 kg) were assigned to either vertical drop jump (VDJ) or horizontal drop jump (HDJ) group training twice a week for 10 weeks. Participants performed 5-8 sets x 6-10 repetitions of vertical-alternate (VDJ) or horizontal-alternate (HDJ) one-leg drop-jumps, landing from the top of a platform 25 cm in height. Before and after training, several performance, kinetic and kinematic variables were assessed. The HDJ led to greater improvement of the sprint-time (-8.5% vs. -4% ; p<0.05) and COD performance in comparison with the VDJ (-7.9% vs. -1.1% ; p<0.05), while the VDJ caused greater improvement in the vertical jump compared with the HDJ (+8.6% vs. +4.1% ; p<0.05). Moreover, the VDJ regimen compared with the HDJ, induced greater changes in the kinetic variables associated with vertical jumping performance, such as peak ground reaction forces (+10.3% vs. +4.3%), relative impulse (+12.4% vs. +5.7%), leg- spring stiffness (+17.6% vs. +4.6%), contact time (-10.1% vs. -1.5%), and reactive strength index (+7.2% vs. +2.1%) ; all comparisons with p<0.05. Conversely, the HDJ regimen was able to improve the short-distance and COD performances by increasing the step length (+3.5% vs. +1.5% with p<0.05) and reducing the contact time on COD (-12.1% vs. -2.1% with p<0.05) more than the VDJ. This investigation showed the crucial role that specific plyometric regimens play in optimizing similar biomechanical featured functional performances such as jumping, sprinting and COD.

plyometrics – neuromuscular abilities – sprint – agility – team sport

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