Figure 2. Endurance improvement of chronically exercised mice.

A, After familiarization, mice were trained for 6 weeks and sacrificed 3 days after the last bout of exercise. This cohort (“chronic exercise”) was compared to a group of mice that performed one exercise trial (“acute exercise”) and sedentary controls. B, An exercise protocol with incremental speed was chosen for the endurance trial and the daily training. C, Blood lactate measurement in mice after an acute bout of exercise (4h post exercise) and after 3 days of recovery. D–G, Endurance running performance of mice before (pre-exercise) and after (chronic exercise) the 6 week training: running time (panel D), distance (panel E), work (panel F) and power (panel G). Bars are average levels and error bars depict standard deviations. N = 8 animals per group pre-exercise and n = 7 animals per group for the chronic exercise (one mouse died during the training period). *p<0.05.