Fig. 11. Change in force as a function of passive pre-stretch for both muscles. Positive values of force enhancement represent a larger isometric force following a passive stretch. A negative value of force enhancement represents a depression following a passive stretch. The solid, blue points and line represent the data and regression for muscle 178, respectively (force change=1.35+0.20xstrain; R²=0.28; P=0.35). The open red points and broken line represent force change for muscle 179 (force change=-2.62+0.25xstrain; R²=0.065; P=0.18). As stretch distance increased, the variation in force response increased. However, the changes in force in response to a passive stretch were independent of stretch distance in both muscles. For these data, the muscles were stretched at 15 mm s^-1, and stimulated with the 3s pattern. N=4-7 animals for each muscle at each absolute distance of stretch.