Exercise · Lower leg

Calf raise

You rise onto the balls of your feet and lower back down. Plain, and the base of everything the calf and Achilles do: Momentum's system names inadequate calf load tolerance as the movement failure behind Achilles pain, and load tolerance has to be built somewhere before running asks the tendon for several times body weight on every stride. Bending the knee shifts the work from the gastrocnemius, which crosses the knee, onto the soleus beneath it — which is why both versions exist and why the straight-knee version alone is an incomplete answer.