Climbing Shoe Fit Considerations: Foot Compression

Climbing shoe fit can be tricky, especially for those of us with feet that are outside the normal width/volume measurements. I’ve seen over my years in climbing that some people seem to struggle more than others with shoes. This begs the question of why? I suspect the answer lies partially in sensitivity, as some people are more susceptible to the sensation of movement inside a shoe than others. However, there are also other differences in feet (besides just width and volume) that can impact climbing shoe fit.

Drawing on my experience as a dancer (especially in how pointe shoes are fit), one of these other considerations is foot compressibility. This is exactly like it sounds in that it measures how much the foot compresses inward and thus how much it will conform to the shape of the shoe (whatever shoe you are wearing). To check your foot compressibility, stand flat without shoes on. Then, place your thumb and first finger on the metatarsals outside the foot near the toes and try to squeeze. The amount your foot squishes inward is the amount of foot compressibility you have. The picture below shows where to squeeze.

But, how does this impact climbing shoe fit and what can you do about it? If a foot has a lot of compressibility, then as you move around on a climbing route and weight different parts of your foot, it will compress inside the shoe. This can create movement making your climbing shoes feel sloppy even if they seemed to fit when standing on flat ground. The second issue is with crack climbing. As you torque your foot inside a crack, it will compress here as well. The outcome of this compression depends on the width of the crack and the fit of the climbing shoes you are wearing. If your current climbing shoes have do not compress your foot enough, then both the foot and shoe could be compressed inward, which can result in the shoe/foot getting stuck in the crack. What happens is that as the shoe is pushed inward with the foot, it increases in vertical height. Then when you go to remove your foot it twists inside the shoe but the shoe doesn’t move. Since the foot is moving inside the shoe it becomes very difficult to get the foot/shoe out of the crack.

So, what can you do to help with foot compression? For dancers with a lot of compressibility, pointe shoes are typically sized narrower than the foot width would seem to indicate. Similarly, wearing a climbing shoe that is slightly narrower than your foot can help. However, this is a balancing act. If you go too narrow, then the shoe may cause pain, but, if you don’t go narrow enough, then the issue isn’t fully addressed. How much compression an individual foot has (i.e. how much does it scrunch in during the test) impacts how much narrower you need to size your climbing shoe compared to your foot width. You can do the compressible foot test while trying on climbing shoes to see what kind of movement you may have in a particular shoe.

If your foot is really narrow and compressible, then finding a shoe that is narrow enough to create compression may be difficult. I wouldn’t particularly recommend wearing thicker socks, as they are made out of a material that will also compress and so add another source of potential movement. A thin sock may help, but if it doesn’t add enough compression, it could bunch up or move, causing additional fit issues. Choosing a lace up with laces that extend to the ball of the foot area can help get enough compression on really narrow feet.