The working hypothesis was that a 12-week program of PRT
would increase: (a) the power output of the overall
musculature associated with movements of the ankles,
knees, and hips; (b) the cross-sectional area and the
force and power of permeabilized single fibers obtained
from the vastus lateralis muscle; and (c) the ability of
young and elderly men and women to safely arrest
standardized falls. The training consisted of repeated
leg extensions by shortening contractions of the leg
extensor muscles against a resistance that was increased
as the subject trained using a specially designed
apparatus