Understanding Slopers and Passive Stress on Fingers
If you’ve been climbing for a while, it's easy to understand that hanging below slopers uses much more friction (pink shading, above) than on other hold types.
The more skin surface area, the better to apply force downward on the hold.
Because slopers have a downward slope and typically don't have sharp edges, the fingers' joint angles tend to be more obtuse (larger), considering this position through the lens of the length-tension relationship (the length of a muscle and its tensile strength), it's not optimal for force generation.
This position puts the wrist in a more "passive" position than grabbing onto smaller, flatter holds.
Conversely, When the wrist is in extension (think half or full crimping), the length-tension relationship of the finger and wrist flexors improves.
Because of this hold shape, we rely more on the passive structures (joint capsules, ligaments, and titin) to balance below the hands.
As soon as the skin contact ends, the wrist is loaded in flexion to create a plumb line below.
This position puts a lot of stress on the ligamentous structures of the wrist.
If we consider the average exposure this position puts on the wrist ligaments, think about the additional load put on them when a climber is fatigued.
In that context, the muscular component (active) further reduces the ability to protect the joint, relying more heavily on the ligamentous structures.
Key takeaways:
Modify the hold type frequently.
Don't add weight to sloper practice; it's a skill.
Strength train to improve forearm recruitment.
End your session when coordination drops .