Understanding A3 Pulley Abuse

The A3 pulley is the third most common finger injury in climbers.

Often climbers feel like they've injured the collateral ligaments of the finger (green lines), which is less common. Indeed, the sides of the PIP joint undergo stress with climbing, but the rotational pressure to the A3 pulley and volar plate is more significant.

The A3 pulley can tolerate more abuse than the A2 and A4 because of its attachment point (the volar plate). This "plate" is a thickened portion of the joint capsule that crosses the joint. Volar refers to the palm side of the hand, and plate refers to this thickened portion.

By contrast, the A2 and A4 pulleys are fibro-osseous. They attach directly to a more rigid structure (outer lining of the bone called the periosteum). That is why the A3 can tolerate more pulling and twisting; there's more "wiggle room".

This rotational stress to the fingers is riskiest, and why frequent fingerboard use will always be a helpful tool. It is our version of strength training the fingers for climbing. We can say it's protective because it has…

• More time under tension / set.

• More directional control (less rotation).

• Easily quantified loads. All we need is above the average intensity of climbing (per individual).

• More of the same grip type (customized for the individual).

Takeaways

• In my opinion, the fingerboards primary use is to counterbalance the performance stresses of rock climbing. It's the thing that reduces all that stiffness we get from climbing too much. Without that regular strength training style load, we increase our injury risk slightly with lots of rotation.

• Another thing we can say is that the fingerboard isn't specific enough to transfer to the sport directly. So, don't be frustrated if your fingerboard gains aren't making you send harder immediately. That is not the point. Climbing is more complicated than hanging on your fingers. But you should still do it!