Height of jump reflects the explosive force of leg muscles: myth or reality?

Spring is an integral physical ability, which depends on other physical abilities: strength, velocity, coordination. The aim of this work is to prove, referring to theoretical assumptions and experimental data, that spring as a physical ability has dual expression. In some cases it is important to a sportsman to jump high, no matter how long it takes to make a spring; in other cases it is important to him to reach the same altitude as quickly as possible. In the first case the height of jump, determined by take-off force impulse, is what matters, in the second case the time of jump, determined by dynamic force, which determines the time of movement, is important. 14 members of Lithuanian juniors' handball team have been examined. They have performed three jumps each on the force platform without an amortizing squat. We have estimated the take-off time tats, time of darting in the air tlėk, velocity at the moment of the abruption off support v0, body mass center's (MC) maximum raise off the ground (hMC), average take-off force (Fvid), absolute dynamic force (dF/dt)max and relative dynamic force (R). Founding our and other authors' research data on theoretical presumptions we may state that: a) the height of jump does not depend on dynamic force, but does depend on force impulse; b) the time of jump depends on dynamic force; c) spring as human physical ability must be defined not only by height of jump, but also by speed of jump. These two aspects of jump, different in qualitative terms, reflect different speed-strength characteristics; d) the most appropriate measure for estimating spring as complex human physical ability is relative power of jump. [ABSTRACT FROM AUTHOR]