Get bouldering hold types right: how to safely grip open hand, half-crimp, and pinch as a beginner – and why the full crimp is off-limits for now.
Is it enough to just squeeze a hold as hard as you can? The honest answer: no – and that's exactly what causes most climbing injuries. At the bouldering gym you'll run into countless hold shapes – from huge jugs to rounded slopers to tiny crimps. What matters isn't which hold you see, but how you grip it.
Upper-extremity injuries make up 57.6% to 78% of all climbing injuries – so more than every second one, up to nearly four out of five – and almost half of these fall directly on the fingers. The A2 and A4 pulleys, which hold the flexor tendons close to the finger bone, are hit most often.
Biomechanical studies show: different grip types ("grip families") distribute load completely differently across the flexor muscles (flexor digitorum profundus [FDP] and superficialis [FDS]) and tendons. The right grip doesn't just determine your endurance – it protects you from serious overuse injuries. This guide builds clean, safe grip technique from the ground up.
As a beginner, the open-hand grip is your absolute default. The fingertip joint (DIP) is slightly bent, the middle joint (PIP) stays nearly straight. This position creates a gentle, flat line of force.
This keeps the flexor tendon extremely close to the bone and the load on the A2 pulley minimal. Because almost only the deep flexor (FDP) works here, you save energy and fatigue more slowly.
On edges too small for the open-hand grip, the half-crimp comes into play. The middle joint (PIP) is bent stably to about 90 degrees – essentially a right angle in the middle finger joint – while the fingertip joint (DIP) rests with a slight curve.
Mechanically, this grip offers the best ratio of force transfer to stability: the deep (FDP) and superficial flexor (FDS) share the load perfectly. The pulley bears more load than with the open-hand grip, but stays within a safe range when applied cleanly.
A pinch grip locks onto vertical edges or protruding volumes – the thumb presses opposite the fingers. Anatomically, this is one of the strongest grip types, because it fully engages the thumb musculature.
Beginners especially forget the thumb – use it for stabilization whenever you can.
Climbing biomechanics is never just about the hand. Climbing physiotherapist Alice Turner emphasizes: the open-hand grip only works with the right body position – hips low and close to the wall, arms fairly straight.
Only then does the force vector pull ideally downward and away from the hold ("drag"), maximizing friction and preventing slippage. If your hips hang too far from the wall, the force vector tips unfavorably and your fingers have to hold much more.
The full crimp has extremely bent middle joints (PIP) and hyperextended fingertip joints (DIP), often with the thumb locked over the index finger. It offers a huge advantage on tiny holds but creates an extremely sharp angle in the tendon path.
The full crimp isn't a default grip – it's a risky specialist tool for advanced climbers and competition situations ("redpoint cruxes").
Climbing exerts immense peak loads on connective tissue and tendons, which adapt far more slowly than muscles. In the full crimp, the "bowstringing" effect occurs: extreme flexion lifts the flexor tendon away from the bone and pushes hard against the small pulleys.
Measurements by Schweizer (2001) show: in the full crimp, the load acting on the A2 pulley is three times as high as the force at the fingertip. For a recreational climber, that means forces close to 400 newtons – roughly 40 kg of pull on a single finger, right around the pulley's rupture point! As a beginner, consistently avoid this grip.
Trust the science, not your gut feeling: many climbers (even advanced ones) massively overestimate their strength in the half-crimp and believe it's where they're strongest.
But studies on a 23-millimeter campus board – edges deep enough for the first finger segment – clearly show: there, the joint-friendly open-hand grip even produces slightly higher maximum forces than the half-crimp. Actively train your system to tolerate open finger positions – you'll climb safer, and in the long run, even stronger.
### Which grip is safest for beginners? The open-hand grip – your absolute default when starting out. It keeps the flexor tendon close to the bone and puts minimal load on your A2 pulley, since almost only the deep flexor works. Use it consistently whenever the hold allows, and switch to the half-crimp only when edges get too small.
### Is the full crimp really as dangerous as everyone says? Yes. The full crimp creates the "bowstringing" effect: your flexor tendon lifts off the bone and presses on the A2 pulley with three times the force at your fingertip – for recreational climbers that's close to 400 newtons, roughly 40 kg of pull on a single finger. That's right around the pulley's rupture point.
### Why does the thumb matter so much in a pinch grip? The pinch is anatomically one of the strongest grip types, but only when your thumb actively presses against your fingers. Without that counter-pressure you instantly lose stability and leave huge strength potential on the table. Beginners especially forget this – train yourself to consciously engage the thumb on every pinch.
### Is the half-crimp really stronger than open hand? Surprisingly, not always. Studies on a 23-millimeter campus board – deep enough for the first finger segment – show the joint-friendly open-hand grip even producing slightly higher maximum forces there than the half-crimp. Many climbers overestimate their half-crimp strength purely subjectively – trust the measurements instead.