Lower limb biomechanical factors associated with Achilles tendinopathy in runners: a systematic review

Background: Variations in lower limb biomechanics can predispose to Achilles tendinopathy (AT). However, evidence on lower limb biomechanical factors associated with AT in runners is limited. Aims: This review aimed to examine the existing literature systematically to identify lower limb biomechanical factors associated with AT in runners. Methods: SCOPUS, ScienceDirect, and PUBMED databases were searched in April 2021 to investigate various lower limb biomechanics such as kinetics, kinematics, muscle activity, plantar pressure, and temporospatial parameter variables during running among AT patients. Results: Ten studies reported significant differences in knee flexion angle, ankle dorsiflexion, ankle eversion, touchdown angle, and plantarflexion moment between runners with and without AT. Plantar pressure and the ground reaction force variables were also found to be significant discriminators. Muscle activity of tibialis anterior, as well as medial and lateral gastrocnemius during various running phases showed significant differences associated with AT. Runners with AT displayed a longer duration of eversion and over-pronation compared to healthy controls. The mechanical effects of orthotic shoes in runners were able to reduce the incidence of AT. Conclusions: The findings of the current review indicated the biomechanical factors that could contribute to AT among runners. These factors can be assessed in clinical settings to minimise the injury risk among runners. The protocol of the review was registered at PROSPERO (CRD42021237500) on 18th March 2021.