High frequency ultrasound identified (A) decreased circular standard deviation indicating increased collagen alignment after more dorsiflexed immobilization for one week (1W90 and 1W20). Fatigue parameters were also improved for these groups including (B) laxity. Tendons immobilized in dorsiflexion (1W20) were (C) significantly longer than those immobilized in full plantarflexion (1W160). Dotted line in C shows average uninjured tendon length (8.9 mm). 1W160, one week of immobilization at 160°, red; 1W90, one week of immobilization at 90°, orange; 1W20, one week of immobilization at 20°, yellow. Data is represented as mean+SD. Significance (p<0.025) is indicated with solid black lines.