Treadmill exercise

Male mice (n = 6 for each genotype) were accustomed to the treadmill (Columbus Instruments) with a 15 min run once per day at 10 m/min for 3 days. For the next 5 days, mice were subjected to forced running exercise performed on a 10% positive incline at 10 m/min for the first 20 min followed by 40 min at 15 m/min. At the end of the experiment, mice were sacrificed and soleus, plantaris and medial gastrocnemius muscles were collected for analyses. Age-matching males (n = 6 for each genotype) that were not subjected to exercise were used as sedentary control.

For the run to exhaustion experiment, mice were run at 10 m/min for the first 10 min (0–10 min), at 12 m/min during 10–30 min and 14 m/min during 30–60 min. After 60 min, the speed was increased by 2 m/min every 5 min until a mouse was unable to perform. All mice used for these experiments were males (n = 6 per group for each genotype), aged 5–6 months.