ABSTRACT:Ankle dorsifl exion range of motion (ROM) typically decreases aft er prolonged immobilization. Anterior-to-posterior talocrural joint mobilizations are purported to increase dorsifl exion ROM and decrease joint stiff ness aft er immobilization. Th e purpose of this study was to determine if a single bout of Grade III anterior-to-posterior talocrural joint mobilizations immediately aff ected measures of dorsifl exion ROM, posterior ankle joint stiff ness, and posterior talar translation in ankles of patients who had been immobilized at least 14 days. Ten physically active patients (5 males, 5 females; age=21.4+3.3 years) participated. Each had the ankle immobilized following a lower extremity injury for at least 14 days and presented with at least a 5° dorsifl exion ROM defi cit compared to the contralateral ankle. A crossover design was employed so that half of the subjects received joint mobilizations fi rst and half of the subjects received the control intervention (no treatment) fi rst. All subjects ultimately received both treatments. Active dorsifl exion ROM was assessed with a bubble inclinometer, and posterior ankle stiff ness and talar translation were assessed with an instrumented ankle arthrometer. Aft er a single application of grade III anterior-to-posterior talocrural joint mobilization, dorsifl exion ROM and posterior ankle joint stiff ness were signifi cantly increased. Th ere was also a trend toward less posterior talar translation immediately aft er mobilization. Th e trend toward decreased posterior talar translation and increased posterior ankle joint stiff ness supports the positional fault theory. Correction of an anterior talar positional fault off ers a possible explanation for these results.