Purpose: The purpose of the present study was to evaluate lower limb kinematics and muscular activities during walking, side-turning while walking, and side-cutting movement in athletes with chronic ankle instability and compare the results to those of athletes without chronic ankle instability.
Methods: Lower limb kinematics and muscular activities were evaluated in 10 athletes with chronic ankle instability and 10 healthy control athletes using a three-dimensional motion analysis system and surface electromyography during the 200-ms pre-initial contact (IC) and stance phases while walking, side-turning while walking, and side-cutting.
Results: During walking or side-turning while walking, there were no significant differences in kinematics or muscle activities between the subjects with and without chronic ankle instability. For the side-cutting task, however, ankle inversion angles during the 200-ms pre-IC and late stance phases [effect sizes (ESs) = 0.95-1.43], the hip flexion angle (ESs = 0.94-0.96) and muscular activities of the gastrocnemius medialis (ESs = 1.04-1.73) during the early stance phase were significantly greater in the athletes with chronic ankle instability than in the healthy control athletes.
Conclusions: Alterations of kinematics in athletes with chronic ankle instability were found not only at the ankle but also at hip joints during the side-cutting movement. These alterations were not detected during walking or side-turning while walking. The findings of the present study indicate that clinicians should take into account the motion of the hip joint during the side-cutting movement in persons with chronic ankle instability.
Level of evidence: III.
Keywords: Ankle biomechanics; Ankle sprain; Motion analysis; Neuromuscular control; Turn.