CHANGES IN LOWER LIMB JOINT RANGE OF MOTION ON COUNTERMOVEMENT VERTICAL JUMPING

Humans naturally perform a countermovement (CM) action in order to attain a certain height or distance in jumping. This CM action initiates many movement coordination principles such as increasing lower limb joint range of motion (ROM) to allow the performer to be in a more effective position for jumping. In a study where the knee joint ROM was experimentally controlled Moran and Wallace (2007) reported a 17% increase in jump height with a 20° increase in knee joint flexion. Although Moran and Wallace (2007) experimentally controlled two knee flexion ranges, their results revealed a natural increase in hip joint ROM with subsequent increased knee flexion. No study, to the author’s knowledge, has managed to identify the possible relationship between knee and hip joint ROM during a CM jump. The aim of this study is to examine the relationship between hip and knee joint ROM during CM vertical jumping and to determine if there are optimum joint flexion ranges at the hip and knee for jump height