Malamud et al.
Subjects lay prone on a table with a foot securely strapped to a pedal.
A servomotor controlled ankle position, velocity and acceleration. Position, velocity, acceleration and torque signals, as well as EMG from soleus and medial gastrocnemius were sampled at 2 kHz and analyzed using Spike2 and Matlab software. A least-squares approach gave a scalar factor that minimized the difference between the measured torque and foot acceleration. This factor was used to compute the inertial torque component that needed to be subtracted from each trial. For all 11 subjects, at all levels of effort, ankle stiffness reached its peak value 30-40 ms after start of stretch, when the ankle had rotated JAH was a visiting professor funded by the Swedish Central Association for the Promotion of Sports.