Skeletal muscle sarcomere. (A and B) Sarcomere lengths (SL), measured from Z-disc to Z-disc, are shown for the case with the C-zone overlapping with thin filaments (A) and with the C-zone having no thin filament overlap (B). Thick filaments containing myosin are shown as thick green lines and interdigitating thin filaments containing actin are shown as blue lines. Skeletal MyBP-C molecules are shown in sets of seven orange stripes on the thick filaments. Note that only the I-band region increases in length as SL is extended beyond 3.1 µm. In Robinett et al. (2019), thin filaments are assumed to be ∼1.05 µm in length (Greaser and Pleitner, 2014).