A novel registration strategy to transform skeletal muscle architecture during passive shortening

In this study we explored if displacement fields, derived from registration of high-resolution anatomical images in different foot positions, could be used to transform muscle fiber architecture from plantar-flexed to dorsi-flexed foot position (passive shortening). Our data revealed that muscle fiber architecture from one foot position can be transformed in the other foot position and that the original and transformed fibers demonstrate similar architectural characteristics, i.e. fiber lengths, pennation angle, curvature, and physiological cross-sectional area.