Activity levels over 24 in juvenile and adult mdx and control mice.

<p>The height of each column represents the mean value (error bars represent 1 SE; n = 8/group) for the total activity (measured as beam break counts) for each group of mice. Total activity was significantly less in mdx mice at both ages, although the difference decreased with age. The difference in activity levels occurred largely during the dark period when mice are active. At both ages ambulatory (horizontal movement) and rearing (vertical movement) were significantly lower in the mdx than control mice.