Fig. 7. Total isometric force (active + passive force) at the final length (f),
passive force for a muscle stretched from 0 mm to 9 mm (p), and total
isometric force following muscle stretching of 3 mm, 6 mm, and 9 mm (3, 6 and
9, respectively) to the final length for representative tests at a stretching
speed of 3 mm s-1 (A), 9 mm s-1 (B), and 27 mm
s-1 (C). Note the passive force enhancement following deactivation
of the muscle for the actively stretched tests at all speeds, but not for the
passively stretched muscle. These steadystate passive forces persisted for the
duration of observation (5-10 s after deactivation) but were abolished
following shortening of the muscle to -10 mm. Also note the increase in
passive force enhancement with increasing magnitude of active muscle
stretching, and the similarity in magnitude of total force enhancement (while
the muscle was activated), and passive force enhancement for the 9 mm stretch
magnitudes. A summary of the corresponding results across all muscles is given
in Table 3.
