Force-length relation for tetanic contractions (n = 10). The theoretical (thick line) relationship is obtained from ter Keurs et al. (1984) with a plateau extended from 2.26 μm to 2.43 μm and a zero overlap intercept on the descending limb occurring at 3.79 μm. The DT is given relative to the maximum force obtained in each preparation, and the passive force has been subtracted, as explained in the methods section. Note that the shape of force-length relation does not change substantially with temperature. Force appears to drop to zero at a sarcomere length of approximately 3.9 μm (thin line, representing 2nd order polynomial least squares fit).