Fig. 6.

The effect of squeezing on force generated by 6 physical models with various reinforcing fiber angles. Models were connected to a force transducer at constant length, pretensioned to an initial “active” force of 10 N via stretching of the internal latex core, and squeezed at 260 mmHg with a pneumatic pressure cuff. Mean fiber angles (measured from photographs of models taken immediately prior to squeezing) and SDs (gray horizontal error bars) are displayed for each model. Forces immediately before squeezing (gray circles) and after squeezing (black circles) are reported. Squeezing decreased tensile force in models with relatively high fiber angles oriented more perpendicular to the long axes of models. Squeezing increased tensile force in models with relatively low angles more parallel to the long axes of models. Triangular markers indicate minimum and maximum mean collagen fiber angles observed in the ECM endomysium (white triangles; ref. 22) and perimysium (gray triangles; ref. 21) of skeletal muscle fixed at either very short or very long lengths.