Figure 1.

Left: passive tension vs. sarcomere length for fibers (open squares) and bundles (open circles) in elderly subjects. Fibers N = 11, cross-sectional area (CSA) 7718 ± 1499 μm², bundles N = 11 CSA 18,360 ± 2648 μm², (mean ± SEM), average 5 fibers in each bundle. Right: passive tension vs. sarcomere length for fibers (filled squares) and bundles (filled circles) in young subjects. Fibers N = 12, fiber CSA 7777 ± 886 μm², bundles N = 13 CSA 25,115 ± 2095 μm², (mean ± SEM), average 5 fibers in each bundle. Data are shown as mean value +/- SEM (standard error of the mean), after interpolation with a cubic function as described in Experimental Procedures section.