Do habitual foot-strike patterns in running influence functional Achilles tendon properties during gait?

The capacity of foot-strike running patterns to influence the functional properties of the Achilles tendon is controversial. This study used transmission-mode ultrasound to investigate the influence of habitual running foot-strike pattern on Achilles tendon properties during barefoot walking and running. Fifteen runners with rearfoot (RFS) and 10 with a forefoot (FFS) foot-strike running pattern had ultrasound transmission velocity measured in the right Achilles tendon during barefoot walking (≈1.1 ms−1) and running (≈2.0 ms−1). Temporospatial gait parameters, ankle kinematics and vertical ground reaction force were simultaneously recorded. Statistical comparisons between foot-strike patterns were made using repeated measure ANOVAs. FFS was characterised by a significantly shorter stance duration (−4%), greater ankle dorsiflexion (+2°), and higher peak vertical ground reaction force (+20% bodyweight) than RFS running (P −1) and running (≈130 ms−1) than RFS (P <.05). Functional Achilles tendon properties differ with habitual footfall patterns in recreational runners.