Calf tightness reduces how freely the ankle can move because the main posterior muscle–tendon units surrounding the ankle are stiff and less compliant. The calf muscles (gastrocnemius and soleus) cross the ankle joint and act to push the foot downward (plantar flexion) and, when lengthened, to allow the foot to move upward toward the shin (dorsiflexion). When you try to dorsiflex, you lengthen the calf-tendon unit. If the calf is tight, this lengthening is resisted, so you can’t dorsiflex as far as normal—especially with the knee straight, since the gastrocnemius crosses both the knee and ankle. If you try plantar flexion, the muscle-tendon unit must shorten to move the foot downward. A tight, stiff calf also resists this shortening and the surrounding tissues (like the Achilles tendon and fascia) limit how far you can go, reducing end-range plantar flexion. In short, tight calves curtail the ankle’s range in both directions, so both plantar flexion and dorsiflexion can be limited. Inversion involves different joints and muscle groups, so it’s not primarily affected by calf tightness.