Coordination variability in runners after surgical Achilles tendon repair

Abstract

The purpose of this study was to compare lower extremity coordination variability between runners with history of Achilles tendon rupture and healthy controls. Twenty participants, 10 Achilles tendons repaired and 10 controls, were recruited. The groups were matched according to age, sex, volume of running, speed, body mass, height, and footfall type. Achilles tendon mechanical properties were determined using a sonographic technique. A motion capture system was used to record running kinematics. A vector coding technique was used to investigate segment coordination variability and the mean phase angle. Statistical parametric mapping was used to examine the relationship in coordination variability between groups. Higher foot eversion and shank internal rotation coordination variability were found in participants with a history of Achilles tendon rupture compared to healthy controls during the portion of the stance phase between 47.2% and 50.3% when the maximal ground reaction force occurs. The current study provides the empirical evidence for increased coordination variability in a specifically affected group of runners. Altered coordination variability between the foot and shank may indicate a risk of abnormal loading of the musculoskeletal structures of the lower extremity in runners with a history of Achilles tendon rupture.