Fig. 8

Electromyogram of the soleus muscle during stress loading. a A representative chart of electromyographic activity for the no-CS (NCS/Pre) and CS groups on day 6 of CS. b Profile of muscle activity prior to and during stress loading. Muscle activity was obtained via the integration of spike power for 6 diurnal hours (12:00–18:00) and 6 nocturnal hours (0:00–6:00) for each CS day. The activity observed during the 6 diurnal hours (12:00–18:00) of the pre-stress-loading period (Pre-d) was defined as 100%. Pre-n, the 6 nocturnal hours (0:00–6:00) of activity prior to stress loading. All points represent the average +/− standard error of the mean (SEM) from four animals. White circle, % index of diurnal muscle activity; black circle, % index for nocturnal muscle activity. n = 4. *p < 0.05, **p < 0.01 vs. Pre-d. One-way ANOVA