ELECTROMECHANICAL DELAY AND LEG –SPRING STIFFNESS IN YOUNG AND OLDER MEN

Abstract

This study compared leg-spring stiffness and electromechanical delay times in muscles of older and younger adult males. Vertical leg-spring stiffness measures were obtained from 10 older males and 12 younger males who completed drop jumps on a force-sledge apparatus from a drop height of 30 cm. Electromechanical delay times were also obtained on the ankle plantar flexors while performing a simple heel raise activity. The results indicated that younger males produced 24% longer EMD times and 58% higher leg-spring stiffness scores compared with older males (p <0.001). These results suggest that younger males jumped using a stiffer overall leg-spring but older males have a stiffer tendon contribution to overall leg–spring stiffness.