Look at your hand. Put it flat on a table. Your middle finger sticks out past the ring finger, the index is shorter still, and your pinky barely keeps up.
Now picture all four of those fingers on a flat hangboard edge and ask yourself how they're supposed to share the load equally.
They can't.
Flat Edges Have a Loading Problem
What actually happens when you hang on a flat edge is that your middle and ring fingers do most of the work. They reach deeper onto the hold, make better contact, absorb more force. Your index and pinky are basically along for the ride.
Vigouroux et al. (2008), Fuss & Niegl (2012), and Hartley et al. (2023) all measured different force levels at each finger's tendon on flat edges. The fingers that are already your strongest get trained the hardest, while the weaker ones coast. And the middle and ring fingers taking that extra load are more prone to overuse injuries — A2 and A4 pulley strains, mostly.
If you've had that thing where one finger is sore after a hangboard session and the others feel fine, this is probably why.
What's an Unlevel Edge?
It's a training hold where the surface isn't flat. The edge height varies across the width, stepping up or curving, so each finger meets the hold at a different level. When you place your hand on it, all four fingers land in a half-crimp position at the same time instead of your middle finger being deep on the hold while your pinky barely hangs on.
The idea is simple: match the edge height to each finger's length and you get more even force distribution across the hand. Design-wise, some edges use discrete steps — individual plateaus for each finger. Others use a smooth continuous curve. Both do the same thing.
Why Bother?
When all four fingers actually share the load, you recruit muscle fibers across all four flexors instead of overworking two. That means better overall finger strength over time. On real rock you don't get to choose which fingers touch the hold, so training them as a unit makes more sense than letting two of them do everything.
The injury angle matters too. The theory is that more even force distribution reduces the compression and shear stress on the DIP (fingertip joint) and PIP (middle knuckle joint) that's associated with pulley injuries. The research on force imbalance across fingers is well established — the direct link to injury rates on unlevel vs. flat edges hasn't been studied yet, but the biomechanical logic is sound. If you've dealt with finger problems before, or if you're rehabbing one now, reducing load concentration on your strongest fingers is a reasonable way to manage risk.
One thing people don't expect: you can often hang more weight on an unlevel edge than a flat one at the same depth. All four fingers are actually contributing. In our testing and from user reports, some climbers see 10–25% more load capacity. You were already that strong. Your flat edge just wasn't letting you use it.
Who Should Use One?
If you're newer to climbing, an unlevel edge teaches good loading habits early. Your weaker fingers learn to pull their weight from the start instead of developing imbalances you'll have to fix later. If you're doing structured hangboard training, it's useful for heavy loading phases where you want max recruitment across all four fingers. If you're coming back from a finger injury, the more even load distribution is easier on healing tissue.
They're also solid for crag warm-ups. Toss a portable no-hang block in your pack, clip some weight to it, and get all four fingers warmed up evenly before you touch rock. Beats crimping down on a random flat edge in the parking lot.
An unlevel edge doesn't replace flat edges. Climbers have gotten strong on flat hangboards for years and they still work. But if you want all four fingers doing their share, and you'd rather not find out the hard way that your middle finger pulleys have been absorbing too much load, it's a smart addition.
Our Block
Our Unlevel Edge Block has variable edge height with an average depth of 28mm and a 20mm flat active grip surface that supports the DIP joint. The radius is generous enough that longer sessions and repeated sets aren't uncomfortable.
We make them in multiple sizes because hand width varies a lot. Measure from the edge of your pinky pad to the outside of your index pad in millimeters and pick accordingly. If your hands are unusually wide or narrow or otherwise weird (no judgment), our Dual Edge Block Series might be a better fit, or just reach out and we can do custom.
Works for max hangs, warm-ups, rehab, whatever.
Your fingers aren't the same length. Seems weird that we've been training them on holds that pretend they are.
References
Vigouroux, L., Quaine, F., Paclet, F., Colloud, F., & Moutet, F. (2008). Middle and ring fingers are more exposed to pulley rupture than index and little during sport-climbing: a biomechanical explanation. Clinical Biomechanics, 23(5), 562–570. PubMed
Fuss, F.K. & Niegl, G. (2012). Finger load distribution in different types of climbing grips. Sports Technology, 5(3–4), 151–155. Taylor & Francis
Hartley, C., Taylor, N., Chidley, J., Baláš, J., & Giles, D. (2023). Handedness, bilateral, and interdigit strength asymmetries in male climbers. International Journal of Sports Physiology and Performance, 18(12), 1390–1397. PubMed