The Relationship between Leg Stiffness and The Stretch-Shortening Cycle Efficiency During Vertical Jump in Female Athletes

Leg stiffness is the main parameter in mass-spring model of human movement and its correlation to success of some sports performances has been previously presented. The current study was performed to determine the relationship between leg stiffness and stretch-shortening cycle efficiency during vertical jumps. 12 elite female squash players (age 22.8 ± 5.9 yrs, weight 60.62 ± 3.37 kg, height 165 ± 0.06 m) volunteered to the study and performed the hopping test at 2.2 Hz and two vertical jumps, squat jump and countermovement jump. Leg stiffness was measured using hopping test data and was normalized by body mass. Difference in jump height between two jumps was considered as the criterion of stretch-shortening cycle efficiency. Normalized leg stiffness showed positive significant correlation to difference in jump height. On the base of this result, enhancing the leg stiffness may improve the stretch-shortening cycle efficiency in vertical jump and the similar movements.