Mf. Bobbert et Aj. Vansoest, EFFECTS OF MUSCLE STRENGTHENING ON VERTICAL JUMP HEIGHT - A SIMULATION STUDY, Medicine and science in sports and exercise, 26(8), 1994, pp. 1012-1020
In this study the effects of systematic manipulations of control and m
uscle strength on vertical jump height were investigated. Forward dyna
mic simulations of vertical squat jumps were performed with a model of
the human musculoskeletal system. Model input was STIM(t), stimulatio
n of six lower extremity muscles as function of time; model output was
body motion. The model incorporated all features of the musculoskelet
al system of human test subjects considered salient for vertical jumpi
ng, and the initial body configuration was set equal to that of the te
st subjects. First, optimal STIM(t) was found for a standard version o
f the model (experiment A). A satisfactory correspondence was found be
tween simulation results and kinematics, kinetics and electromyograms
of the test subjects. Subsequently, optimal STIM(t) for the standard m
odel was used to drive a model with strengthened muscles (experiment B
). Jump height was now lower than that found in experiment A. Finally,
optimal STIM(t) was found for the model with strengthened muscles (ex
periment C). Jump height was now higher than that found in experiment
A. These results suggest that in order to take full benefit of an incr
ease in muscle strength, control needs to be adapted. It is speculated
that in training programs aimed at improving jumping achievement, mus
cle training exercises should be accompanied by exercises that allow a
thletes to practice with their changed muscles.