Since northern Alabama is so full of vertical caves, the local cave rescue team has a class about 3 times a year. I took that class a few months ago. And then the local caving club also has vertical practice every couple of weeks where they rig ropes inside of a gym just so people can practice.
There are 500 foot deep pits within 45 minutes of my house, so I'm looking forward to getting into those.
Ha-ha.....I think they are still made, maybe not. Strap to one foot and the opposite knee. Let you ascend the rope by leg power, like walking up stairs Fastest way to climb up a rope
It sounds similar to the rope walker or Mitchell system. I'm using the Frog system, which uses the croll ascender on the waist. The rope walkers are generally faster and more efficient, but they're more expensive, considerably bulkier, and much more complex.