Background: Compared with male athletes, female athletes demonstrate increased dynamic valgus angulation of the knee during landing from a jump, although prior to maturation male and female athletes have similar forces and motions about the knee when they land from a jump. Our hypothesis was that musculoskeletal changes that accompany maturation result in poor neuromuscular control of the knee joint in female athletes.
Methods: One hundred and eighty-one middle-school and high-school soccer and basketball players—100 girls and eighty-one boys—participated in the study. Dynamic control of the knee joint was measured kinematically by assessing medial knee motion and the lower-extremity valgus angle and was measured kinetically by assessing knee joint torques; the values were then compared between female and male athletes according to maturational stage. Lower-extremity bone length was measured with three-dimensional kinematic analysis.
Results: Following the onset of maturation, the female athletes landed with greater total medial motion of the knees and a greater maximum lower-extremity valgus angle than did the male athletes. The girls also demonstrated decreased flexor torques compared with the boys as well as a significant difference between the maximum valgus angles of their dominant and nondominant lower extremities after maturation.
Conclusions: After girls mature, they land from a jump differently than do boys, as measured kinematically and kinetically.
Clinical Relevance: Following the onset of the pubertal growth spurt, female athletes change the way that they land from a jump. This change may be due to decreased neuromuscular control of the knee and may explain why the risk of anterior cruciate ligament injury is higher in girls than it is in boys. The measures of neuromuscular control of the knee used in this report may be employed to monitor athletes and to direct appropriate new interventions to athletes at high risk for injury.
1 Cincinnati Children's Sports Medicine Biodynamics Center, 3333 Burnet Avenue, MLC 10001, Cincinnati, OH 45229-3039. E-mail address for T.E. Hewett: firstname.lastname@example.org