Abstract
The purpose of this study was to determine modulation of pre-activity related to different types and heights of deep jump. Sixteen soccer players
with similar training experience (The First Cadet League; age 15; average height 176.8±7.2cm; average weight 61.9±4.6kg), who participated in the study, were performing three types of deep jump (bounce landing - BL, counter landing – CL and bounce drop jump - BDJ) from three different heights (40cm, 60cm and 80cm). Surface EMG device (1000Hz) was used to determine activity of five muscles (mm.gastrocnemii, m.soleus, m.tibialis anterior, m.vastus lateralis) within 150ms before touchdown. All muscles, except m.gastrocnemius medialis, showed systematic increase in pre-activity when platform height was risen. The most significant difference was between values of pre-activity obtained for 40cm and 80cm platforms. Within variety types of deep jump, the most significant difference in pre-activity was between landings versus bounce drop jump, where certain amount of pre-activity was used for performing the take-off. In initial period of training program practicing landings should provide high quality landing during variety types of deep jump. Deep jumps from the height above the optimal one are not an adequate exercise to precisely adapt muscle activity for the impact.