Our work using motion-capture guided ultrasound imaging to measure dynamic variation in the Achilles tendon moment arm in vivo during walking has been accepted for publication in the journal Computer Methods in Biomechanics and Biomedical Engineering. This work was performed in collaboration with our colleagues at the University of Wisconsin-Madison.
Abstract. The Achilles tendon (AT) moment arm is an important determinant of ankle moment and power generation during locomotion. Load and depth-dependent variations in the AT moment arm are generally not considered, but may be relevant given the complex triceps surae architecture. We coupled motion analysis and ultrasound imaging to characterize AT moment arms during walking in 10 subjects. Muscle loading during push-off amplified the AT moment arm by 10% relative to heel strike. AT moment arms also varied by 14% over the tendon thickness. In walking, AT moment arms are not strictly dependent on kinematics, but exhibit important load and spatial dependencies.