Crimp

A crimp is a hold, or a way of gripping a hold, where the fingers bend sharply at the middle joint with the fingertips pressed down onto a thin edge. This grip position lets climbers hold onto surprisingly small ledges of rock or plastic, but it concentrates a lot of force through the finger tendons and pulleys compared with a more open handed grip.

Full crimping, where the thumb wraps over the top of the index finger to lock the position, generates more holding power than an open crimp but also loads the finger joints more aggressively, which is part of why crimp heavy climbing and crimp heavy hangboard training carry a real risk of pulley or tendon injury if introduced too quickly.

Building comfort with crimps generally means progressing gradually, warming up thoroughly before pulling hard on small edges, and mixing in open handed grip positions rather than crimping everything by default. Route setters and outdoor climbs use crimps at every grade, so learning to read when a hold calls for a full crimp versus a more relaxed grip is a skill worth developing with time rather than force.