When ascending a crack, climbers utilize various techniques to ensure they stay in the crack. While face climbing, a climber's center of gravity changes frequently as he reaches and stretches her arms and legs to grab holds all over the wall. Crack climbing is different because climbers are typically following one line (a fissure) up the wall. Thus, their weight tends to stay centered, while their hands and feet are in line with the crack. Crack climbing also differs in that in order to get up a crack, a climber must stick his fingers, hands, feet or toes directly into the crack by utilizing the "jamming" technique. This means a climber inserts her fingers, hands or other body parts into the crack to get purchase to ascend the rock. Discover a few valuable tips to be a better crack climber.
As with any type of climbing, rather than focus on pulling yourself up the rock by utilizing hand jams and finger jams, be sure to jam your feet and toes into the crack as much as possible and press up on those jams (use those jams as footholds). Jamming is a difficult technique to grasp at first, so make it easier on yourself by focusing on your shoe-clad feet. You will also alleviate some of the tears and burns you will surely get while your hands slide around inside the crack as you learn to jam.
When jamming your toe or foot into a crack, turn your foot so that the inside of the ankle faces up, and then stick your toe or foot into the crack, press sideways and down, and then stand up. Remember to actively use your legs. It feels unnatural, but good footwork will make crack climbing much easier.
You can do either a thumb-up finger jam or a thumb-down finger jam. Thumb-down finger jams are more common because you can often twist your index and middle finger into a crack for good purchase. First, slot your two fingers into the crack (or three or four fingers depending on how deep the crack is), then twist your hand down and away from the crack. This will cam your fingers into the crack, which means you'll be pulling down on one side of the crack with the insides of your fingers and pressing against the others side of the crack (to a lesser degree) with your outside fingers. Play with your thumb as you do this. Sometimes it can add significant support to a jam if you press up with it against your fingers. Tape your fingers with white athletic tape if you are climbing sharp cracks or sandstone cracks to ensure you don't rip or tear your skin off as you are learning.
Good hand jams are like big jug holds, but even better if done correctly. No matter how pumped you are while climbing, if you get the perfect-sized hand crack, you should be able to hang out forever. Still, for the beginner, hand jamming doesn't feel natural. Try practicing on the ground first. Stick your hand in a crack, set it by twisting it, and then press your thumb into your hand, while you press the sides of the crack with the sides of your hand. You are basically camming your hand in a crack and then flexing the muscles in your hands. Thumb-up and thumb-down techniques are common, so practice both.
Definitely wear tape when you are learning how to hand jam. More than likely if you don't wrap your hands in tape, you will get "gobies," which are cuts, tears and scrapes your hands and knuckles acquire when they slide around inside cracks.
Wide crack Jamming Tips
Getting the hang of climbing wide cracks can be tough. Neither your fingers nor your hands will get purchase in a wide crack. Sometimes you can use your fist by jamming it in the crack and clenching it, or you can utilize a "cupped" hand. Other times, you'll have to stick your entire arm or side of your body into the crack. One tip to consider for climbing wider cracks is rather than climbing by simply bringing one hand above the other (as most people naturally try to do at first), try shuffling your hands. You can do this by making a fist jam, palm down, with your right hand, and then making a fist jam, palm up, with your left hand. Lean to the side of the rock that correlates to your top hand, and then shuffle your hands up inside the crack by sliding one at a time and keeping purchase with the other. Wear tape on your hands and long-sleeves shirts when climbing wider cracks to ensure you don't tear your arm and hands to pieces.