Interaction of foot and hip factors identifies Achilles tendinopathy occurrence in recreational runners.

OBJECTIVES: To investigate the interaction of ankle-foot complex and hip joint factors with Achilles Tendinopathy (AT) occurrence in recreational runners.

DESIGN: Cross-sectional.

SETTING: Research Laboratory.

PARTICIPANTS: 51 runners, 26 healthy and 25 with AT.

MAIN OUTCOMES MEASURES: Shank-forefoot alignment (SFA), weight bearing lunge test (WBLT), passive hip internal rotation (IR) range of motion (ROM), hip external rotators (ER) and ankle plantar flexors (PF) isometric strength. CART analyses were performed to assess interactions that could distinguish those with AT.

RESULTS: Passive hip IR ROM, ankle PF torque, SFA, and hip ER isometric torque were associated AT occurrence. The model correctly classified 92% of individuals without AT and 72% of those with AT. The area under the receiver operating characteristic curve was 0.88. Interaction factors revealed in nodes 3 and 10 were statistically significant. In node 3, runners with more than 29.33° of passive hip IR ROM had a 130% increased likelihood (PR = 2.30) of AT. Node 10 showed that individuals with higher PF torque, SFA varus, ER torque, but reduced passive hip IR ROM had an 87% increased likelihood (PR = 1.87) of AT.

CONCLUSION: Interactions between hip and foot factors could accurately classify recreational runners with and without AT.