Effect of testosterone supplementation plus low-intensity physical training on grip strength, spontaneous physical activity, and respiratory activity in old male mice.

<p>(<b>A</b>) Forelimb grip strength measured at baseline (wk 0, N = 8 per group, C: control, T: testosterone) and after 7 weeks of (N = 6 for control, N = 8 for T group) testosterone supplementation (10 mg/kg, sc, twice per week). Control was injected with an equal volume of vehicle (0.1 ml). (<b>B</b>) Spontaneous physical movements recorded as total counts of infrared beam breaking per min. Each animal was housed individually in a metabolic cage. Results were averaged separately over the light and dark periods. The measurement was performed during week 6 after testosterone supplementation (N = 4 for each group). Xtot, Ytot, Ztot each denotes movements in X-axis, Y-axis, and Z-axis. (<b>C</b>) Mean respiratory activity recorded as oxygen consumption and carbon dioxide production for animals individually housed in a metabolic cage (N = 4). Results were normalized to total body weight. All results are shown as mean ± SEM, and the difference between control and testosterone groups at each time period was analyzed by <i>t</i> test. ns, not significantly different.