All of the MSK ultrasound assessments were performed with a portable B-mode imaging device and a multi-frequency linear-array probe. Care was taken to maintain minimal pressure with the probe against the skin to avoid any tendon compression. AT-CSA was determined by a transverse scan at the level of the medial malleolus with the probe placed perpendicular to the AT. A standoff pad was used along with transmission gel.

AT-thickness was determined by a panoramic scan with the probe oriented longitudinally moving continuously along the AT from the calcaneal insertion to the musculotendinous junction of the gastrocnemius. Care was taken to maintain consistent speed of movement and pressure.