Crimp vs Open Hand vs Drag: The Mechanical Differences Explained

Crimp vs Open Hand vs Drag: The Mechanical Differences Explained

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.

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.

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.

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.

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.

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.

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.

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.

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.

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