As climbing has progressed from simple vertical faces to more complex topography of the rock wall, largely brought on by recreational bouldering, so too have the techniques. One of these is the heel hook. It’s as if the first climber said to him or herself, “hey, that’s like an extra pair of hands down there. Let’s use those!”
And so began at least the documented use of the heel hook, specifically using the back of the heel to put pressure on a hold using your hamstrings. When climbers tell you that you should be using your legs more, they generally didn’t mean this. At least not with gusto, because this paper is a case series of 17 injuries from using this technique.
Now, I know what you’re saying. Lower extremity injuries are a small subset of climbing injuries (~5 to ~13%), and most of those are from falls instead of from using the heel as a climbing implement. But this should be looked at more closely, as the authors of this paper state that nearly 2/3rds of their patients were coming for a second opinion due to initial misdiagnosis.
So what injuries do you get from this? All of the climbers in the case series state that while using the heel hook, they had sudden dorsal pain in the knee, thigh, or pelvis. Seven reported a snapping sound as if a ligament had torn. All had a noticeable limp immediately, and point tenderness on exam. With US and MRI, the authors discovered 8 strains, and 9 torn muscles or ligaments. Of note, only 2 required surgery, and the rest were treated conservatively.
Interesting enough is that 6 of the tears were in the pelvis (5 in the biceps femoris alone) in a pattern more common with soccer (football) players,. The 2 knee injuries were similar to those of martial arts injuries from a similar but different heel hook. The velocity there leads to more ACL injuries however.
Prevention is obtained (in the words of the authors) by thorough stretching and flexibility exercises, and a good warmup routine. They also note that people should not use the heel hook ambitiously, as knowing their own limits will prevent injury. They also feel that MRI is not necessarily overkill for pelvic injuries and professional climbers.
The “Heel Hook”—A Climbing-Specific Technique to Injure the Leg