The location of your foot plant on the pedal of the Cybex Rotary Calf
changes the recruitment of the plantar flexion muscles. Forefoot plant
effects more effort from the medial head of the gastrocnemius and the
more proximal areas of the plantar flexor muscles. A more midfoot plant
effects the more lateral and more distal areas of the plantar flexor
muscles.
Also, the midfoot plant allows a heavier load to be lifted as there is a
mechanical advantage with the resistance lever shortened. The Rotary
Calf Machine exercises the ankle in 1st-Class Lever mode, unlike a
Standing Calf Raise, which exercises the ankle in 2nd-Class lever mode.
In the Rotary Calf Machine (1st-Class Lever), the fulcrum is the the
ankle joint, the resistance lever extends from ankle joint to the
midfoot or forefoot/ball of foot, and the force lever extends from the
ankle joint to the heel insertion attachment of the Achilles Tendon.
In the Standing Calf Raise (2nd-Class Lever), the fulcrum is the the
ball of the foot, the resistance lever extends from the ball of the foot
to the ankle joint holding the weight of the body,, and the force lever
extends from the ball of the foot to the heel insertion attachment of
the Achilles Tendon.
— mb