['Exercise training (ET) and physical activity (PA) offer obvious health benefits in regular participants. In pre-clinical animal models, treadmills and running wheels are the models of choice for intervention studies using ET and PA. However, the frequency and duration necessary for positive effects on health are not completely understood. We investigated the impact of short duration voluntary wheel running on body composition in FVB × C57BL/6\u2009F1 hybrid mice over 22 weeks. Mice were randomized and given access to voluntary wheel running (N = 6) or locked wheels (N = 5) for 1 hour per night during the dark cycle, 5 days per week.', 'Average weekly running distance was generally cyclic in nature over the 22 weeks but did not change significantly from week to week, except for a difference between week 3 and week 9 (P = 0.05). Daily running distances ranged from 0.78 km to 1.45 km. Compared with non-runners, runners demonstrated significantly lower relative fat mass (9.98 ± 0.56% vs. 14.91 ± 1.47%, P = 0.0067) and significantly higher relative lean mass (79.18 ± 0.65% vs. 75.41 ± 1.28%, P = 0.019). No differences were observed with respect to glucose metabolism.'] Does a novel long term short interval physical activity regime improve body composition in mice?