EMC, FORCE, AND POWER ANALYSIS OF SPRINT-SPECIFIC STRENGTH EXERCISES

This study was undertaken to compare force-time characteristics, muscl e power, and electromyographic (EMG) activities of the leg muscles in maximal sprinting and in selected bounding and jumping exercises. Seve n male sprinters performed maximal bounding (MB), maximal stepping (MS ), maximal hopping with the right (MHR) and left (MHL) legs, and maxim al sprint running (MR). These ''horizontal'' exercises and running wer e performed on a force platform. EMG activity was telemetered unilater ally from five leg muscles during each trial. The results indicated si gnificant (p < .001) differences among the studied exercises in veloci ty, stride length, stride rate, flight time, and contact time. Also, s ignificant differences were noticed in reactive forces (p < .01-.001) and power (p < .01) among the performances, whereas only insignificant differences were observed in EMG patterns. The average resultant forc es during the braking and propulsion phases in MS, MHR, and MHL were g reater (p < .001) than in MR and MB. Stepping and hopping are cyclic a nd sprint-specific and may be used as strength exercises for sprinters because of great strength demand.