A Correlation Study of Lower-Limb Gait Biomechanics with Clinical Severity in Patients with Achilles Tendinopathy

Background: Biomechanical characteristics have been recurrently associated as aetiological factors in Achilles tendinopathy. Despite this, no study has investigated the relationship between biomechanics and clinical severity. Aim: To establish whether an association exists between Achilles tendinopathy clinical severity and biomechanical kinetic and temporospatial variables. Methods: Design: Observational cross-sectional cohort study. Setting: Gait laboratory. Participants: Twenty-four participants with mid-portion Achilles tendinopathy. Main outcomes: Gait kinetic and temporospatial parameters were measured using an instrumented treadmill. Clinical severity was measured using the Victoria Institute of Sport Assessment-Achilles Questionnaire. Results: Overall clinical severity was reduced in participants with a greater step length (B = 2.144, p = 0.04) and a greater anteroposterior displacement of center of pressure (B = 0.117, p = 0.02) and increased in individuals with a greater step time (B = -343.861, p = 0.05). Pain was greater in participants with a greater weight acceptance peak index (B = -1.058, p = 0.046), impulse (B = -0.108, p = 0.04) and active force peak (B = -0.102, p = 0.025) and reduced in participants with a greater weight acceptance rate (B = 0.004, p = 0.024), stride length (B = 0.374, p = 0.049), step length (B = 0.0755, p = 0.044) and push-off rate (B = 0.003, p = 0.038). Function was reduced in participants with a greater weight acceptance peak index (B = -0.905, p = 0.014) and greater double support time (B = -198.526, p = 0.040). Activity was increased in participants with an increased anteroposterior displacement of centre of pressure (B = 0.061, p = 0.038) and reduced in participants with a greater base of support. (B = -1.500, p = 0.033) Conclusion: Significant correlations between biomechanical parameters and Achilles tendinopathy clinical severity exist. Biomechanical variables identified in this study should be investigated in larger cohorts prior to determining clinical applications.