Differences in Lower Extremity Kinematics Between a Bilateral Drop-Vertical Jump and a Single-Leg Step-down

Jennifer E. Earl, Sarika K. Monteiro, Kelli R. Snyder

DOI: 10.2519/jospt.2007.2202

STUDY DESIGN: Mixed-model, repeated-measures design in a laboratory setting. OBJECTIVES: To examine the differences in hip, knee, and ankle kinematics between a bilateral drop-vertical jump and a single-leg step-down. A secondary purpose was to examine gender differences in kinematics of the tasks. BACKGROUND: Both a drop-vertical jump and step-down task have been used to evaluate lower extremity movement and injury risk. The differences in joint angles between these tasks have not been reported. METHODS AND MEASURES: Three-dimensional joint angles of the hip, knee, and ankle of 19 females and 18 males were evaluated with a high-speed camera system while they performed a bilateral drop-vertical jump and a single-leg step-down. Maximum joint angles were compared between tasks and genders using ANOVA models. RESULTS: When averaged across both genders, the step-down produced greater rearfoot eversion (12° compared to 8°) (P‹.0005), and hip adduction (16° compared to 1°) (P=.03) than the drop-vertical jump. Females had greater hip internal rotation in the step-down than in the drop-vertical jump (5° compared to 2°) (P=.02). When averaged across both tasks, females had greater knee abduction than males in both tasks (4° compared to 0°) (P‹.0005). CONCLUSIONS: The unilateral step-down task produced greater motion in the frontal and transverse planes at the ankle and hip, and would be appropriate in evaluating control of the hip during movement. The bilateral drop-vertical jump produced greater knee abduction in both genders, and may be appropriate for evaluating excessive knee abduction as a risk factor for non-contact anterior cruciate ligament injury, for example. The 2 tasks appear to challenge the neuromuscular system in different manners, and both should continue to be used in the investigation of injury risk.

J Orthop Sports Phys Ther. 2007;37(5):245-252; published online 15 March 2007. doi:10.2519/jospt.2007.2202

KEY WORDS: ACL, biomechanics, gender, hip, knee

This study found that the unilateral step-down task produces greater motion in the frontal and transverse planes at the ankle and hip, and would be appropriate in evaluating control of the hip during movement. The bilateral drop-vertical jump produces greater knee abduction in both genders, and may be appropriate for evaluating excessive knee abduction as a risk factor.

View Full Article