Ankle Joint Kinetics in Runners with Medial Tibial Stress Syndrome

Abstract

Medial tibial stress syndrome (MTSS) is a common overuse running injury. While numerous studies have reported abnormal ankle kinematics in runners with MTSS, to date, no studies have evaluated ankle kinetics in this population. PURPOSE: To compare ankle kinetics in runners with and without MTSS. METHODS: Participants included eight runners with MTSS (sex: 7M/1F; age: 35 ± 11.3 years) and eight matched controls (CON; sex: 7M/1F; age: 35 ± 8.7 years). Kinematics and ground reaction forces were recorded while participants ran overground. Sagittal plane kinetics were calculated about an axis connecting the malleoli while frontal plane kinetics were calculated about an axis approximating the 23° medially deviated and 42° inclined orientation of the subtalar joint. Joint work was calculated by integrating the joint power curves. Paired t-tests were used to compare peak moments, powers, and work between MTSS and CON groups. RESULTS: Neither peak plantar flexor (MTSS: 2.14 ± 0.53, CON: 2.24 ± 0.57 Nm/kg) nor peak invertor (MTSS: 1.04 ± 0.34, CON: 1.16 ± 0.32 Nm/kg) moments were different between groups (p = .720, p = .472, respectively). There were no differences in sagittal plane powers or work between groups. In the frontal plane, the MTSS group demonstrated lower peak positive power (MTSS: 1.97 ± 0.38, CON: 3.05 ± 1.12 W/kg, p = .021), and performed less negative (MTSS: -0.09 ± 0.02, CON: -0.16 ± 0.07 J/kg, p = .032), positive (MTSS: 0.14 ± 0.03, CON: 0.22 ± 0.07 J/kg, p = .039), and total (MTSS: 0.23 ± 0.06, CON: 0.37 ± 0.15 J/kg, p = .032) work. CONCLUSIONS: Compared to healthy individuals, runners with MTSS are not able to generate as much energy to invert their foot during late stance. This may explain why previous studies have observed runners with MTSS have prolonged rearfoot eversion during stance.Figure 1: Frontal plane joint moments (A) and powers (B). The solid line represents the CON group and the dotted line represents the MTSS group. Error bars show one standard deviation above and below the mean curve for the CON group.