Figure 3.

Analysis of X-rays for a SCP subject after talus alignment. A. The foot in a position similar to that when exerting 0 Nm. Under high magnification markers (dashed lines and arrows) were placed for alignment and at particular insertion points of muscles and along the fibula. Note that, for example, at the navicular bone, subluxation and an extreme position (gapping) of the calcaneo-navicular-joint is noticeable. B. The foot in a position similar to that when exerting 4 Nm dorsal flexion. The talar bone was aligned with that in A. Such talar bone alignment allows distinction of contributions to foot plate movement and muscular length changes by foot deformation and crural bone movements, respectively. The markers of A. were copied to image B. (dashed lines or arrows). New markers (solid lines or arrows) placed on the reference points in the new condition. Length changes were estimated (rectangles) for GM (m. triceps surae), TA (m. tibialis anterior) and PB (m. peroneus brevis) and angular changes for the fibula and foot plate. Note that, for clarity, magnification of A. and B. are not identical. The arrow on the heel part of the foot plate is used for calibration (actual dimension = 8.98 cm). C. Inset of the forefoot to show the presence foot lengthening upon exertion of +4 Nm.