Our fingers are some of our smallest extremities. Rock climbers put tremendous strain on their fingers, which can encourage an injury. It’s important to understand the anatomy of the hand and fingers to see what we can do to decrease the risk of climbing injury, and to also have a look at what to do if a finger injury happens.
Our fingers have no muscles, and our hands only have small muscles meant for fine, controlled movement; those hand muscles aren't meant for the powerful explosive force needed for rock climbing. The energy needed for rock climbing comes from the forearms instead. Tendons run from the strong muscles in our forearms, through the wrists and the fingers, to supply the power needed to climb.
After the tendons pass through the wrist and hand, they run through ligaments in our fingers called annular ligaments. Annular ligaments redirect the pull of the tendons to move our fingers. These ligaments are like the guides on a fishing pole that bend a rod when force is applied to the end of the fishing line. It’s the A2 and the A3 annular pulleys of your index, middle, and ring finger that are the most prone for damage when climbing. When griping with and open hand grip, there is very little pressure put on the pulleys in the fingers. When griping with a crimping grip, the fingers are put in danger. When people start to climb, it can feel like there’s more strength using a crimp position. With practice, an open hand grip will feel more comfortable and strong. When you are climbing at your max, trying to get up a climb beyond your limits (which I strongly recommend you do to increase your skill), you will come across holds that you just need to crimp.
When you come across a hold you just can’t get with an open hand grip, try to use a grip half way between a crimp an open hand. When in a full crimp grip you can take a little force off your tendons and ligaments in your finger by placing your thumb on top of your index finger to add a little extra strength and support.
It takes a long time to develop climbing skill. Some people will start out doing 5.8 and 5.9 while others will start with 5.4 and 5.5. No matter where you start, anyone can end up climbing the 5.11’s and 5.12’s, it just takes time, effort, and patience. Regardless of how long you have been climbing or your skill level, your muscles will develop strength faster than your tendons and ligaments. You can easily increase your climbing power in a few months to a level that your ligaments and tendons can’t handle, which can lead to tendinitis, sprains, pulley injuries, and many other very uncomfortable problems that will put your climbing on hold.
So take your time. Train hard but be smart. Push your limits but not all day. Once you start feeling pain in your fingers, go down a grade or two or stop your session and stretch out. Don’t keep pulling on that crimp over and over again; you can come back to it in a few days.