Apparatus and Subject
Positioning
Subjects were seated in a straight-back chair mounted on an elevated platform. Attached to the platform were a footplate and torque device for producing dorsiflexion of the right ankle (Fig. 1). The height and depth of the footplate were adjusted to align the subject's medial malleolus with the axis of rotation of the torque device. Through seat angle adjustments, the right knee was set in 60 degrees of flexion from full extension
to relieve stretch on the gastrocnemius and plantaris muscles. The torque device consisted of two circular and rotational plywood disks, joined by a wooden footplate and heel stop. The device could be locked into a resting position with the ankle angle at 90 degrees. A steel chain, extending from a bolt on the elevated platform to a bolt
on one of the disks, prevented rotation of the device during a maximal voluntary
contraction (MVC) of the plantar flexors. Running in a groove over the top of each disk was a rope attached to a weight. When the device was unlocked,the smaller of the two weights applied dorsiflexion torque of 9.0 N • m. So that an increased dorsiflexion torque could be applied, the free end of the rope was raised and attached to a metal
rod, thus suspending the weight. Constant applied torques were calculated to be 35.5 N-m during the stretching procedures. For four subjects (before a minor modification was made in the device to make the applied torques constant), the small applied torque was 7.5 N • m, and the large applied torque varied between 31 and 33 N • m.