Figure 6. Stiffness measurements at 2 ms after the stretch.

A, force response (upper trace) to length steps (middle trace) and average axial distortion of motors (Δz, lower trace). Test steps of amplitude ±1 nm hs⁻¹ were imposed at T₀ (left column) and at 2 ms after the conditioning stretch (right column). B, T₁ points for the test steps (open symbols) and T_i points (filled symbols, the force just before the test step) for T₀ (circles) and four different conditioning stretches of size ΔL, identified by the symbols as indicated in the table in the inset. e/e₀, reported in the table, are the slopes of the linear regressions (continuous lines) fitted to the T₁–T_i points, relative to that at T₀. Data from one fibre. C, e/e₀ (open circles) and e_m/e_m0 (filled circles) obtained with the test steps at 2 ms after the stretch versusΔL (mean ±s.e.m., 9 fibres). Open and filled triangles are the respective values obtained at 2 ms after the stretch with 4 kHz length oscillations (from Fig. 5). D, e_m/e_m0versusΔz at 2 ms after the stretch (same data as filled symbols in C). The continuous line is the data fit of the equation: e_m/e_m0=A (Δzⁿ)/(kⁿ+Δzⁿ) + 1.