Panel A. Percent of pixels with elevated muscle T2 recovered to baseline values ten days after downhill running (* denotes significant difference from baseline, p < 0.05). Panel B. Transaxial, T2-weighted images from the lower hindlimb of an mdx mouse before and after a single bout of downhill running for 45 min (−14 degrees, 8–10 m/min). Note specific area of hyperintensity in the medial region, between the tibia and fibula, which is recovered after 10 days. Panel C. Three-dimensional rendering of a single mouse hindlimb showing region of muscle damage in the medial compartment.