Equatorial x-ray reflections from contracting muscle after an applied stretch.

The equatorial X-ray reflections were recorded from contracting muscle after a slow stretch. The intensity ratio of the 1,0 to the 1,1 reflections (I10/I11) after the stretch was not significantly different from that during an isometric tetanus at the same sarcomere length, although the tension after the stretch was considerably greater than isometric. This suggests that an almost identical number of cross-bridges produce a greater tension after a slow stretch than during an isometric tetanus.