Slant Board Calf Raise
How to do it
Stand on a slant board or step edge with your heels lower than your toes, one foot only. Use a wall for balance. Rise up onto your toes through full range, squeeze at the top, then lower slowly past the level of the board so your heel drops below your toes. Control the descent.
Why it's good for runners
The dropped-heel position stretches the Achilles at the bottom of every rep, which is what makes this useful for tendon rehab and for runners with stiff ankles. The deeper range builds calf strength through the full motion your ankle goes through in running.
Common mistakes
Cutting the bottom range short defeats the entire point — let your heel drop. Don't lean forward to make it easier, and don't progress to single-leg work until you've owned the full range with both feet.