Author(s): SHIOUCHI, M., SHOJI, K., MANABE, Y., Institution: CHUKYO UNIVERSITY, Country: JAPAN, Abstract-ID: 649

INTRODUCTION:
Ankle sprains are common in sports. Chronic ankle instability (CAI) is recognized as one of the sequelae of ankle sprains. Furthermore, the stop-jump is a commonly used jumping movement in many sports such as basketball, soccer, and volleyball. However, little is known about the biomechanical characteristics of single-legged stop-jump performance in individuals with CAI.
The purpose of this study is to examine the characteristics of single-legged stop-jump performance with CAI.

METHODS:
This study presents a preliminary case comparison between one CAI participant and one healthy control. The CAI was defined using the inclusion and exclusion criteria published by the International Ankle Consortium (1), and a Cumberland Ankle Instability Tool (CAIT) score of less than 24 (2). Each participant performed 5 times single-legged stop jump (SSJ) with 1-step approach run. The motion of markers was captured with a 12-camera motion capture system (Vicon, Oxford, UK, 250Hz). During the dynamic trials, ground reaction force (GRFs) were collected synchronously with marker trajectories using one ground-embedded force plate (Kistler, Switzerland, 1000Hz).
RESULTS:
Jump height was comparable between participants (approximately 0.37 m).
However, the participant with CAI demonstrated substantially greater hip positive work during the propulsion phase compared with the control.
CONCLUSION:
These findings may indicate increased reliance on proximal joint contribution to compensate for reduced ankle function, consistent with previous reports of proximal compensation strategies in CAI populations (3).
Although limited to a preliminary case comparison, CAI may achieve jump heights comparable to those of healthy individuals by utilizing a hip-focused strategy during jumping.
These findings suggest that individuals with CAI may compensate for ankle dysfunction by increasing reliance on proximal joints during single-legged stop-jump tasks.

References
(1) Gribble, P. A., Delahunt, E., Bleakley, C., Caulfield, B., Docherty, C. L., Fourchet, F., & Wikstrom, E. A. (2013). Selection criteria for patients with chronic ankle instability in controlled research: A position statement of the international ankle consortium. Journal of Orthopaedic & Sports Physical Therapy, 43(8), 585–591.
(2) Kunugi S, Masunari A, Noh B, Mori T, Yoshida N, Miyakawa S. Cross-cultural adaptation, reliability, and validity of the Japanese version of the Cumberland ankle instability tool. Disability and rehabilitation. 2017 Jan 2;39(1):50-8.
(3) Cathleen N. Brown., Darin A. Padua., Stephen W.Marshall., Kevin M. Guskiewicz. (2011) Hip Kinematics During a Stop-Jump Task in Patients With Chronic Ankle Instability. Journal of Athletic Training, 46(5):461–470.