358 Journal of Sport Rehabilitation, 2009, 18, 358-374 © 2009 Human Kinetics, Inc. Changes in Active Ankle Dorsiflexion Range of Motion After Acute Inversion Ankle Sprain James W. Youdas, Timothy J. McLean, David A. Krause, and John H. Hollman Context: Posterior calf stretching is believed to improve active ankle dorsifexion range of motion (AADFROM) after acute ankle-inversion sprain. Objective: To describe AADFROM at baseline (postinjury) and at 2-wk time periods for 6 wk after acute inversion sprain. Design: Randomized trial. Setting: Sports clinic. Partici- pants: 11 men and 11 women (age range 11–54 y) with acute inversion sprain. Inter- vention: Standardized home exercise program for acute inversion sprain. Main Out- come Measure: AADFROM with the knee extended. Results: Time main effect on AADFROM was signifcant (F 3,57 = 108, P < .001). At baseline, mean active sagittal- plane motion of the ankle was 6° of plantar fexion, whereas at 2, 4, and 6 wk AAD- FROM was 7°, 11°, and 11°, respectively. Conclusions: AADFROM increased sig- nifcantly from baseline to week 2 and from week 2 to week 4. Normal AADFROM was restored within 4 wk after acute inversion sprain. Keywords: kinematics, ligament, edema, rehabilitation Sprains of the lateral ligaments of the ankle are the most common injury sus- tained during sports participation. 1,2 The mechanism of injury typically involves trauma to the ankle–foot complex whereby the ankle is forcefully plantar fexed and the foot is inverted. 3 Acute stretching or tearing of the ligaments and fbrous capsule of the ankle joint results in bleeding, joint effusion, and loss of joint range of motion. During the acute phase of rehabilitation the rehabilitation profession- al’s primary goals are to protect the injured tissues and minimize the amount of ankle-joint effusion. This treatment combination involves protection in the form of an ankle brace or gait aids, rest, ice, compression, and elevation (PRICE). 4–6 Impaired active ankle-joint dorsifexion range of motion (AADFROM) is considered an indication of severe ankle-joint injury. 7 Reduced AADFROM after Youdas, Krause, and Hollman are with the Program in Physical Therapy, and McLean, the Charlton L-C Sports Medicine Center, Mayo Clinic, Rochester, MN 55905.