Assessment of Football Player Hip Joint Motion During Vertical Step Down Movement

Harkins, K., McGinley, S., Carruth, D. W., Hale, B., & Knight, A. (2011). Assessment of Football Player Hip Joint Motion During Vertical Step Down Movement. Proceedings of 2011 Annual Meeting of the Southeast Chapter of the American College of Sports Medicine. Greenville, SC.

Abstract

Lower extremity kinematics have been examined during different motions, including jumping, landing, squatting, and cutting exercises, primarily among healthy participants. Very little research has examined these variables among elite athletes. There is a need to determine these movement patterns among healthy, elite level athletes to establish normal movement patterns and to identify abnormalities that may occur after injury. The purpose of this study was to examine the motion of the hip joint during a vertical step down exercise and compare the dominant to the non-dominant leg among elite level athletes. Eight healthy NCAA Division I football players (height = 1.87 + .06 m; mass = 99.22 + 18.84 kg) completed the testing. The participants performed three repetitions of a vertical step down exercise off a 25.4 cm for both the dominant and non-dominant leg. The testing leg was placed on the side of the box, with the non-testing leg in slight hip flexion and full knee extension. The participants were instructed to squat down until the heel of the non-testing leg tapped the floor, and then return to the starting position. Three repetitions were performed. The participants’ hip joint motion in the sagittal plane was recorded during the exercise using a motion analysis motion capture system. The data was analyzed with a 2 (range) by 2 (leg) ANOVA with repeated measures on the last factor. The results revealed a significant difference (P < .05) in hip motion between the dominant and non-dominant legs, with the non-dominant leg demonstrating 7.06° less hip sagittal plane motion than the dominant leg. These differences may be caused by strength imbalances between the dominant and non-dominant leg, and may potentially increase the potential for injury and affect performance. Future research will examine hip motion in the frontal and transverse planes as well as muscle activity during lower extremity exercises among elite athletes. This study is an initial collaboration between the Center for Advanced Vehicular Systems, the Department of Kinesiology, the Department of Industrial and Systems Engineering, and the athletic department to develop a sport performance program to enhance athletic performance and reduce the potential for injury.