Forearm extensor stretch (tennis elbow)
Elbow · WristStraighten the arm out in front with the elbow locked and the palm facing down. Let the wrist drop, then use the other hand to draw the fingers gently further down until you feel a stretch along the top of the forearm. Hold 30 seconds, repeat 3 times.

Elbow straight, palm down, wrist dropped — stretch felt on top of the forearm.
