Force / Area = Pressure
Therefore, more Force (harder moves) or smaller Area (smaller holds / less ergonomic holds) = more pressure on the fingers. Pretty straightforward math.
Injury prevention is a subject often avoided in routesetting. Usually considered the responsibility of the climber, routesetters who consider injury avoidance are an utterly crucial asset to their gym. Ergonomic setting makes for symmetrical, strong, well-rounded climbers. Unergonomic setting makes for muscular imbalance, shared weaknesses, and injuries. Which set of climbers will be happier? Which gym's competitive teams will perform better?
Healthy, happy climbers rely on routesetters to subtly suggest good climbing habits. This is applicable at any and all grade - from the first-timer complaining about how tight climbing shoes are to the mutant warming up on your hard problems to the 55 year old that throws down on his lunch break.
A jug is not always a jug. What do we know about new climbers?
- They move quickly and inaccurately ("thrutching")
- They weight holds before grabbing them properly
- They are not as good at positioning their body to keep their weight on their feet
- They do not optimize their hand/arm positioning
- They are not experienced enough to recognize when a move or sequence may be dangerous
Let's say a new climber comes into a climbing gym and climbs two VB-rated problems. The problems involve the exact same movement on the same terrain. On one problem, the setters carefully picked each hold to be rounded. On the other, any hold from the "jug" pile is used as the next hold.
Red areas represent surface area of contact with the hold, Area. Assuming the same movement off of each hold, Force remains constant. Note that with the hold on the left, advanced climbers will automatically lean back, straighten their arms, and put more of their hands' contact area on the hold. Beginners will lock the hold in to their chest, endangering their fingers.
"But RC," you say, staring poignantly at your boxes of flat, sharply incut jugs laying in the corner. "If we only set with the comfortable jugs, what do we do with all these things?"
Our job is never easy, and this is one part of it. There are times that unrounded jugs are acceptable. In a steep enough roof, the pressure = force / area argument is largely nullified. Let's rotate the previous example image 90 degrees, as if the holds were in a roof:
More incut holds are a bit friendlier on steep walls.
As you can see from this picture, the goal is to maintain the hold's sharpest point at a 90 degree or more angle away from the climber's plumb line of hand positioning. In other words, when making the move, you want as much surface area of your hand touching the jug as possible. Any time a hold is contacting across one segment/phalange of the fingers is a danger zone for connective tissue. (I am in no way suggesting here that you should intentionally set with sharp holds in a roof - just illustrating the ergonomic difference between profile and incut.)
A good basic rule of thumb is: for vert or gently overhanging, a jug is a hold with a deep profile and a slight incut. For steeper walls, a jug is a hold with a deep incut. It will still be more comfortable if it also has some depth, so that the contact area is a bit more rounded.
Explaining profile vs incut. While it might be slightly harder to make a move from the hold on the right, beginners' fingers will thank you.
If you simply don't have enough comfortable holds, then you get to work extra hard at finding the ideal position for the hold to not be tweaky. This is a fine art.
Some holds, of course, have sufficient incut and profile depth to be usable anywhere with no issue. Most gyms reserve these size of holds for steeper walls anyway, where beginners need the largest possible grip surface and depth possible. These type of "mega jugs" are irreplaceable for a commercial gym - beginners can use them just to hang on, intermediate climbers can make hard moves off of them as they learn how to negotiate large moves on steep terrain without destroying their fingers, and advanced climbers can use them to practice dynos, recovery / power endurance, and campusing. New holds these days are much more comfortable, ergonomic and (in most cases) intelligently designed than they used to be. If your gym has a budget, ergonomic jugs should be a significant part of it.
Let's quickly cover our knowledge of new climbers again:
- They move quickly and inaccurately, so beginner jugs should be mostly grabbable surface, with no extraneous sharp parts
- They weight holds before grabbing them properly, so holds should be fairly uniform
- They are not as good at positioning their body to keep their weight on their feet, so holds should be directly above footholds, especially if they're sharp/incut - never expect beginners to smear.
- They do not optimize hand/arm positioning, so pulling sideways or outwards on holds should be just as safe as pulling down (probably not as functional or "good" of a hold - but safe!)
- They are not experienced enough to recognize when a move or sequence may be dangerous, so don't put them in a dangerous situation.
To summarize: You can't change the amount of force a climber will put on a hold, but you can change the surface area that force will be distributed around. Good routesetting should be fun, but it should also be safe.
In this post I mostly covered the ergonomics of holds, specifically jugs. In the next two parts of this topic, I'll go into a bit more depth on the ergonomics of directionality and movement. Until then, happy setting!