Climbing involves a lot of precise foot placements, awkward gripping positions, and a myriad of other things that the body doesn't like (for instance taking a 30 foot whipper). Often times, especially when climbing an overhanging roof, a climber has to use their toes to dig into climbing holds to keep the body from taking said whipper. The core muscle play a really important part of keeping the hips near the wall, but everyone knows they need to be doing more situps and less sitting. How about the muscles inside the foot? They're pretty important for sticking to that hold, so why do we ignore them?
The "intrinsic" muscles of the foot are responsible for modifying how your big calf muscles pull and how your toes flex and extend. They're pretty easy to work on, and here's how:
1. throw a dish towel on the floor.
2. with just your toes, pull the towel towards you. Don't move your heel one spot on the ground, we're just trying to pull the towel and ball it up.
3. you can even throw some weight on top of the towel.
That's it. Simple, easy, and it'll help the climber more adequately meet the wall with their feet.
Run to THIS SITE if you really need a good visual. Or if you have plantar fasc.