Striated muscle fibers: inactivation of contraction induced by shortening

The myofibrils in an isolated muscle fiber remain straight during the early part of a lightly loaded contraction initiated by membrane depolarization, but, as shortening continues, myofibrils in the core of the fiber become wavy, which suggests that their activation has been interrupted by shortening of the fiber. This may be a factor determining the length-tension relation at short muscle lengths.