Advanced climbing often relies on maximizing contact with the rock through specific thumb engagements:
Engaging large muscle fibers by gripping as hard as possible for 3–5 seconds after a slow 1–2 second build-up of force. 3. The Psychology of Experience free solo mature thumbs
When using tiny "crimp" edges, "mature" or highly trained climbers often wrap their thumb over their index finger to increase power and stability. Advanced climbing often relies on maximizing contact with