Key takeaways
- Jamming wedges body parts into a crack to create holds where the face offers none.
- It's the core crack-climbing technique — the skill that makes crack climbing possible.
- Techniques vary by crack size: finger jams, hand jams, fist jams, and wide-crack methods.
- A good jam is secure enough to hang your full weight on; learning to trust jams is key.
What jamming is
Jamming is the fundamental crack-climbing technique of wedging a body part into a crack — fingers, hands, fists, feet, arms, or even the whole body — and expanding or torquing it to create a secure, weight-bearing hold where the open rock face offers nothing to grab. It’s the skill that makes crack climbing possible.
Techniques by crack size
- Finger cracks — finger jams/locks.
- Hand cracks — the classic, secure hand jam.
- Fist cracks — fist jams.
- Offwidths — arm bars, chicken wings, knee and foot jams.
Feet are jammed too (heel-toe and torquing), and matching the right jam to the crack size is essential.
On a steep hand crack with no face holds, a climber jams a hand into the fissure and cups it to lock against the walls, torques a foot in below, weights both to step up, then reaches higher to set the next jam — moving up rock by jamming alone.
Learning to jam
Jamming feels strange and can scrape skin at first, but good jams become secure enough to hang your full weight on. The keys are setting jams correctly for each size and learning to trust and relax into them. It’s the defining skill that, unlike face climbing, unlocks crack routes.
The bottom line
Jamming is the heart of crack climbing: wedging fingers, hands, fists, feet, or your whole body into a crack to make secure holds where the face has none. The technique scales with crack width — from finger jams to hand jams to wide-crack contortions — and the real skill is setting jams well and trusting them. Learn to jam and an entire world of crack routes opens up.
Frequently asked questions
What is jamming in climbing?
Jamming is the technique of wedging a part of your body — fingers, hands, fists, feet, arms, or even your whole body — into a crack and expanding or torquing it so it locks against the crack walls, creating a secure hold. It's how you climb cracks, where there are no holds on the open rock face to grab. Jamming is the defining skill of crack climbing.
What are the jamming techniques by crack size?
They scale with the crack's width: finger jams and finger locks for thin cracks, hand jams (the classic, most secure) for hand-width cracks, fist jams for fist-width cracks, and progressively more awkward whole-limb techniques (arm bars, chicken wings, knee and foot jams) for offwidths. Feet are jammed too, using heel-toe and torquing techniques. Matching the right jam to the crack size is essential.
Is jamming hard to learn?
It can feel strange and uncomfortable at first — quite different from gripping holds on a face, and it can scrape your skin — but with practice good jams become secure and even comfortable. The key skills are learning to set jams correctly for each crack size and, importantly, learning to trust and relax into them rather than over-gripping. Many crack climbers use tape gloves to protect their hands.
Sources
- Crack technique — American Alpine Club
- Climbing skills — The Mountaineers