We have identified the molecular (transcriptional) signatures associated with muscle remodeling in response to rehabilitation in a patient cohort. Subjects with a closed malleolus fracture treated conservatively with 6 weeks of cast immobilization are recruited. Then subjects are enrolled in a 6 weeks structured rehabilitation program focusing on progressive resistance training of the ankle plantar flexor muscles. Phenotypic measurements are performed before (pre-rehab), during (mid-rehab, 3 weeks) and immediately after (post-rehab, 6 weeks) the rehabilitation intervention. The maximal cross-sectional area (muscle size) and peak torque (muscle strength) are quantified using isometric and isokinetic tests in combination with 3D-magnetic resonance imaging. Ankle plantar flexor muscle size and strength measurements are also performed on the uninvolved limb (serves as a control) at 4 months post-immobilization. Measurements are also acquired from the contralateral leg, which serves as an internal control.