Apparent width of WT and DMD ^mdx muscle fibers. Individual and corresponding mean (±SD) values for the apparent width of WT and DMD^mdx fibers (n = 126 fibers from seven animals in each group). Five measurements were taken from each fiber, using equally spaced lines, transverse to the longitudinal axis. Each data point corresponds to the average from these five measurements. Each bar (and superimposed data points) shows data from a same animal. Main graphs show values from fibers used for di-8-anepps, TMRM, and Fluo-4 staining. WT and DMD^mdx values did not significantly differ (P = 0.95, nested t test, 95% CI for the difference between mean values: −7.8 to 8.3). Insets shows values from the voltage-clamped fibers (n = 29 fibers from seven WT animals and 27 fibers from seven DMD^mdx animals. P = 0.17, nested t test, 95% CI for the difference between mean values: −2.4 to 12.0). 95% CI, 95% confidence interval.