LOWER-LIMB DYNAMICS AND ENERGY ABSORPTION DURING THREE DIFFERENCE TYPES OF SINGLE LEG LANDINGS (9 - 16)

Abstract

Journal of Sports Science and Physical Education 3(1): 9–16, 2015 - This research aimed to determine ACL injury risk from the jump landings by observing peak joint moments and energy absorptions. Single leg landings from 3 different jumps which were 1) drop jump (SDL) 2) counter movement jump (SCL), and 3) stop jump (SJL)) were investigated. Sixteen national hockey players of Australia participated in the study and performed all jump tasks, 5 trials each. Twelve high speed cameras, placed around the participants, captured 3D motion at 250 Hz and the force plate recorded the ground reaction at 2000 Hz synchronously. 3-D orientation of reflective markers attached on the athlete’s skin and the recorded ground reaction force were used for computation of moment and energy absorption of the lower limb. One way MANOVA with repeated measure was employed for statistical analysis. Results showed that the greatest peak knee valgus moment (p<0.001) was occurred during SJL. Hence, athletes are likely to get their ACL injured by performing the stop jump landing. In addition, SJL also led to the greatest peak hip abduction and internal rotation moments (p<0.01). The majority of energy absorption was occurred at the ankle joint (54-56%) while muscles around the knee (30% - 41%) and the hip (5-14%) joint contributed to a lesser energy absorption. Energy absorption implied that muscles contracted eccentrically. Since SJL induced the greatest amount of energy absorption at the ankle joint, then muscles around the ankle joint should be stronger in order to prevent injury from SJL.

Keywords: Joint moment, energy absorptions, ACL.