Most climbers choose their grip based on what feels strongest on a given hold. That's the wrong frame. Grip choice is a mechanical decision — it determines where force goes, how much load your pulleys absorb, and how much margin for error you have when fatigue sets in. The difference between half crimp and full crimp on a small edge isn't preference. It's a measurable change in A2 stress.

Climbers talk about grips as if they are “techniques.”
Mechanically, they are load-distribution systems that change the force line, tendon tension, pulley stress, and joint stability.

This article explains the mechanical differences — not stylistic ones — so climbers understand why certain grips feel strong, weak, sharp, or dangerous.

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1. The three grip families (in simplest terms)

1.a Open Hand

• flat finger posture
• DIP almost straight
• minimal PIP bend
• large contact surface
• smooth force line
• low pulley stress
• high fingertip tension

1.b Drag (a subtype of open hand with different mechanics)

• DIP nearly straight
• PIP slightly more bent than open hand
• fingertip “hooks” over the edge
• very high FDP demand
• safer for pulleys, harder for finger control
• grip fails suddenly when the fingertip loses tension

Drag = open hand with more edge contact + more fingertip hook.

2. Half Crimp

• PIP bent to ~90°
• DIP slightly curled
• controlled “hook” shape
• highest stability
• balanced load distribution
• great for training

3. Full Crimp

• PIP deeply flexed
• DIP hyperflexed
• thumb over index
• maximal mechanical advantage
• highest redirect angle
• highest A2 stress

These positions change how force travels through the finger.

Image: Finger Pulleys in flexor system

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2. The mechanical effect on the force line

Every grip alters the curvature of the flexor tendon path:

Open Hand

Force line = smooth, shallow curve.

• tendon stays close to bone
• pulleys see less peak stress
• low mechanical amplification

Half Crimp

Force line = moderate redirect at PIP.

• pulleys take more load
• still stable
• predictable, balanced
• best “strength-to-risk ratio”

Full Crimp

Force line = sharp angle at PIP & DIP.

• A2 gets massive spike
• tendon lifts more easily
• bowstringing risk increases
• high force output, high danger

This is geometry, not opinion.

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3. Tendon loading: FDP vs FDS

Open Hand

• almost pure FDP
• deep tendon takes most load
• fingertip tension very high

Drag

• almost pure FDP
• fingertip hook adds friction
• low pulley load but high tendon tension
• collapses suddenly with fatigue

Half Crimp

• FDP + considerable FDS
• FDS stabilizes PIP
• best load-sharing pattern

Full Crimp

• extreme FDP
• extreme FDS
• no margin for error

Full crimp = maximum tendon load + minimum mechanical forgiveness.

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4. Joint mechanics: PIP & DIP angles

Open Hand

• PIP = minimal flexion
• DIP = slightly hyperextended
• tends to drift when tired
• safer, but unstable under fatigue

Drag

• sloping edges
• rounded lips
• large open-hand slopers with slight catch
• fatigue-friendly, but control-sensitive

Half Crimp

• PIP = stable 80–100°
• DIP = gentle curl
• “locked in” feeling
• most consistent grip under load

Full Crimp

• PIP = extreme flexion
• DIP = sharp hyperflexion
• smallest angle errors → biggest stress

Half crimp maintains angles the best.

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5. Pulley stress differences

Open Hand → lowest pulley stress

Large contact point + smooth force line.

Half Crimp → moderate

Higher redirect angle but stable.

Full Crimp → highest

Sharp angles = amplified A2 stress.

Reducing pulley load = reducing angle curvature.

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6. When each grip is actually useful

Open Hand

• large slopers
• smooth volume edges
• fatigue-friendly grips
• hangboard base work
• tendon-friendly sessions

Half Crimp

• small to medium edges
• finger-strength training
• control-heavy cruxes
• consistent technical climbing
• strongest position per risk

Full Crimp

• desperate small edges
• redpoint cruxes
• micro-edges on vertical walls
• temporary use only

Full crimp is a tool, not a default.

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7. Why some climbers struggle with certain grips

Common reasons:

Weak FDS → weak half-crimp

No PIP control → unstable → fingertip tries to compensate → fatigue.

Weak FDP → weak open hand

Fingertip can’t maintain tension → DIP unrolls → loss of force.

Poor wrist mechanics → bad drag grip

Wrist collapse → force line breaks → grip feels insecure.

High fatigue sensitivity → crimp collapse

Angles drift → bowstringing risk spikes.

Grip preference is usually mechanical, not psychological.

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8. What this means for training

Train open-hand first, always.

If you're building a hangboard protocol, open-hand is the starting position regardless of what grip you use on the wall. It conditions the FDP, keeps pulley stress low, and builds the fingertip tension that every other grip position depends on.

Train half-crimp for strength work.

Half crimp has the best strength-to-risk ratio of any grip. It shares load between FDP and FDS, keeps joint angles stable, and gives you a consistent mechanical baseline session to session. Max hangs, weighted hangs, and repeaters should all default to half crimp.

Reserve full crimp for the wall, not the board.

Full crimp happens naturally on certain holds during climbing. Training it deliberately on a hangboard adds A2 stress without adding proportional strength benefit. Let it appear where it has to — don't manufacture it in training.

The grip hierarchy for training: open hand → half crimp → full crimp. In that order, with that priority.

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Putting it all together

The grip you choose determines:

• how force travels
• how pulleys load
• how tendons share tension
• how stable the joints are
• how safe small edges feel
• how long you can maintain tension

Mechanically:

• Open Hand = safest
• Half Crimp = strongest safe
• Full Crimp = strongest dangerous

Understanding why these differences exist is the foundation for safe finger training and smarter climbing decisions.

Related reading:

• Bowstringing Explained: The Root Cause of Pulley Stress in Climbing
• Finger Pulley Injuries: A2, A3, A4 — Mechanics, Symptoms and Safe Return to Load — what happens after the bowstring spike reaches its limit
  
• FDP vs FDS: What Each Tendon Really Does in Climbing — the two muscles at the center of joint control and angle stability
• How Tendons Really Adapt — And Why Most Climbers Rush It — why pulley adaptation is the slowest link, and how to train around it