Stretch of an activated muscle causes a transient increase in tension that decays, after the stretch, to a level greater than the steady state isometric tension at the corresponding muscle length. We investigated the non-crossbridge contribution to this tension response by inhibiting active crossbridge cycling using three different myosin inhibitors, 2,3-butanedione monoxime (BDM; Bagni, et al., 2002), N-benzyl-p-toluene sulphonamide (BTS; Cheung, et al., 2002) and blebbistatin (Kovacs, et al., 2004). Adult male rats were humanely killed with an intra-peritoneal injection (>200 mgnull;kg^-1) of an overdose of sodium pentobarbitone (Euthatal). Bundles of ~10 intact (fast) fibres (fibre length, L₀, ~2 mm) were isolated from the flexor hallucis brevis and mounted horizontally between a force transducer and a servomotor (initial sarcomere length = 2.5 μm; 20°C). The preparation was housed in a flow-through chamber perfused with physiological solution and continuously bubbled with 95% O₂ and 5% CO₂. Fibre bundles were tetanized and a ramp stretch of 5% L₀ (1 L₀ s^-1) applied on the tension plateau. Stimulation was maintained for a further 500 ms after the ramp where residual force enhancement (RFE; see Edman & Tsuchiya, 1996) was measured. Experiments were repeated with either 10 μM BTS (n=4), 5 mM BDM (n=1) or 10 μM blebbistatin (n=1) added to the control solution. All myosin inhibitors markedly depressed active tension; compared to control, the mean (± SE) maximum tetanic tension decreased to 18 ± 0.02% in BTS. In preliminary experiments using BDM and blebbistatin tetanic tension decreased to 13% and <1%, respectively. The peak incremental tension during stretch also decreased, but to a lesser extent than tetanic tension; relative to control, the peak tension decreased to 61 ± 0.06% in BTS, 28% in BDM and 17% in blebbistatin. In contrast, RFE was not reduced by any of the drugs; relative to control, RFE was 157 ± 0.34% in BTS, 107% in BDM, and 92% in blebbistatin. RFE was also calculated as the residual tension determined by double exponential curve fitting to the tension decay after stretch. The residual tension, relative to the control, was 138 ± 0.24% in BTS, 96% in BDM and 99 % in blebbistatin. Whereas BDM increased the rate of tension decay after stretch, in BTS and blebbistatin the rates were decreased, suggesting that their mechanisms may differ. In all cases, however, myosin inhibitors did not decrease the RFE after stretch indicating that the underlying mechanism is not solely due to active cycling crossbridges.