Longitudinal Sex Differences during Landing in Knee Abduction in Young Athletes

FORD, KEVIN R.1,2; SHAPIRO, ROBERT3; MYER, GREGORY D.1,4; VAN DEN BOGERT, ANTONIE J.5; HEWETT, TIMOTHY E.1,2,6

Medicine & Science in Sports & Exercise:
doi: 10.1249/MSS.0b013e3181dc99b1
Applied Sciences
Abstract

Purpose: The objective of this study was to determine whether biomechanical and neuromuscular risk factors related to abnormal movement patterns increased in females, but not males, during the adolescent growth spurt.

Methods: A total of 315 subjects participated in two testing sessions approximately 1 yr apart. Male and female subjects were classified on the basis of their maturation status as pubertal or postpubertal. Three trials of a drop vertical jump (DVJ) were collected. Maximum knee abduction angle and external moments were calculated during the DVJ deceleration phase using a three-dimensional motion analysis system. Changes in knee abduction from the first to second year were compared among four subject groups (female pubertal, female postpubertal, male pubertal, and male postpubertal).

Results: There were no sex differences in peak knee abduction angle or moment during DVJ between pubertal males and females (P > 0.05). However, pubertal females increased peak abduction angle from first to second year (P < 0.001), whereas males demonstrated no similar change (P = 0.90) in the matched developmental stages. After puberty, the peak abduction angle and moment were greater in females relative to males (angle: female −9.3° ± 5.7°, male −3.6° ± 4.6°, P < 0.001; moment: female −21.9 ± 13.5 N·m, male −13.0 ± 12.0 N·m, P = 0.017).

Conclusions: This study identified, through longitudinal analyses, that knee abduction angle was significantly increased in pubertal females during rapid adolescent growth, whereas males showed no similar change. In addition, knee abduction motion and moments were significantly greater for the subsequent year in young female athletes, after rapid adolescent growth, compared with males. The combination of longitudinal, sex, and maturational group differences indicates that early puberty seems to be a critical phase related to the divergence of increased anterior cruciate ligament injury risk factors.

Author Information

1Sports Medicine Biodynamics Center and Human Performance Laboratory, Cincinnati Children's Hospital Medical Center, Cincinnati, OH; 2Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, OH; 3Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY; 4Graduate Program in Athletic Training, Rocky Mountain University of Health Professions, Provo, UT; 5Department of Biomedical Engineering, Orthopaedic Research Center, Cleveland Clinic Foundation, Cleveland, OH; and 6Departments of Orthopaedic Surgery and Bioengineering, University of Cincinnati, Cincinnati, OH

Address for correspondence: Kevin R. Ford, Ph.D., FACSM, Cincinnati Children'sHospital, 3333 Burnet Ave, MLC 10001, Cincinnati, OH 45229; E-mail: kevin.ford@cchmc.org

Submitted for publication October 2009.

Accepted for publication March 2010.

©2010The American College of Sports Medicine