In reply to AlanLittle:
15 deg overhanging, i.e. a little off vertical.
Some points for others who might take this forward (I think it would make a great sports science dissertation) and because I'm likely to forget if I don't write it down.
1. I asked people "what is the highest grade you have led onsite indoors in the last 12 months?". There were several issues with this. Some down the bottom of the grade range didn't lead. Others were boulders. It was clear that climbers at the top knew exactly what grade they led and that there was a clear difference between 7b and 7b+ to them. Grade 6 climbers were more likely to be wooly. This I think has made the data noisy in the 6th grade and below.
2. I was in Exeter so it was harder to find the same number of 7s as 6s. Hence the R2 is poor as most of data is spread over very little of the x-axis, and as stated above is noisy in the grade dimension.
3. The story line they were given was "hold those two green holds and stand and imagine you are about up to reach for the other green hold over there". For better climbers this led to confusion as some wanted to just to hang low, as they would have done the move dynamically as the target hold was a jug. I tried to tell them to imagine they were on an E5, the gear was shit and the hold of unknown form. But they were sports climbers.
4. A better story would have been, stand up an hover your hand over the target hold. However the grade 5/6a climbers would not have been able to hold the position. This would have been far more accurate in the load dimension of the graph however.
5. Some grade 7 climbers clearly thought the holds so big and the angle of the wall so slight that they saw no reason to bother minimising energy use by using their feet. This was very true of boulderers. One boulderer was removed from the data because of this, as he didn't weight the machine at all. However using smaller holds would have been impossible for the 5/6a camp.
6. Some suggested a better idea was to do a best of three attempts with the very clear story of "put as much weight as possible on your foot"
7. There was friction in the machine. This might make the numbers not equivalent for very light and very heavy climbers.
8. I didn't measure the height of the climbers. Or change the position of the holds depending on the height of the climbers. A very tall climber had the holds near shoulder height, a very short climber was stretched out. This would need controlling for in any repeat test. But would be easy by grouping the climbers in a few bins based on height (this would need a larger sample though)
9. People enjoyed it and engaged well. I believe if the spring balance was replaced with a load cell that was communicating with a mobile phone app (see link to the Norwegian(?) gadget in my previous thread), that a powerful training device would have been created that any wall/coach could use to very clearly demonstrate some truths. For example, how much weight is each member of the youth squad putting on their feet on a 45deg wall. By hanging the phone from the wall infront of the climber's face her/she would be able to play with body position to minimise load on hands and max it on feet. I think naturally good climbers (i.e. those that progress steadily through the grades to say 7b with little physical training) have enough body awareness to natural feel when more weight is on their feet. Others might well not have. I haven't a clue what my feet are doing most of the time, if anything.
I hope someone takes this forward. If they do, I'm happy to help with the rig design, the experimental design, or the stats.
