Effects of developmental stage and gender on lower extremity kinematics and vertical ground reaction forces during landing

Objective : To identify gender and developmental biomechanical differences during vertical jump landings.

Design and Setting : A 2 x 2, developmental stage (pre vs. postpubescent) x gender (male vs female), between subjects design in a controlled laboratory setting.

Subjects : Thirty prepubescent subjects (15 males age = 9.63 ± 0.95 yrs., 15 females, age = 9.19 ± 1.0 yrs.), and 28 postpubescent subjects (14 males, age = 23.57 ± 3.23 yrs., and 14 females, age = 24.22 ± 2.27 yrs.) participated in the study.

Measurements : Subjects performed a vertical jump set at 50% of their maximum vertical jump height ability. Hip and knee kinematics of the dominant lower extremity and vertical ground reaction forces during impact were analyzed.

Results : Significant main effects for developmental stage were found in knee valgus and hip flexion at initial contact, knee valgus, knee flexion, and hip flexion at maximum vertical force, maximum vertical force, impulse and time to maximum vertical force. No gender differences were found among the biomechanical variables measured.

Conclusions : The presence of significant biomechanical differences between children and adults found in this study suggests that physical development influences landing patterns. Gender does not appear to influence landing patterns during a 50% maximal vertical jump landing. Findings add to the body of knowledge regarding developmental and gender comparisons in a functional landing task.

Key Words: anterior cruciate ligament injury, non-contact knee injury, functional movement

2005 Effects of developmental stage and gender on lower extremity kinematics and vertical ground reaction forces during landing. J Athletic Training, Vol 40 (1), 9-14.