In reply to karl walton:
> I shall have to challenge this statement. It may be accurate in some cases, but not all.
> It is quite possible to have long arms and a more normally proportioned body and legs.
but my point is that when you have a positive ape index, do you have normal body and legs and long arms, or do you have short body and legs and normal arms? put another way, is your ape-index positive because your arms are long or the rest of you is short?
it's just a choice of language: the facts, and the reach upwards (though not sideways) remain the same. for upward reach ape-index is irrelevant, or rather, it is only weakly correlated with the true measure of interest, namely shoulder height plus arm length.
anyway, the inforce-outforce lever question is probably more pertinent. i'd like to see a random sample of climbers with their ape-indices and their best top-rope grade (and best trad grade) to see if there is any relationship between ape-index and climbing ability and, if so, in which direction it lies: could be either way.
i think both top-rope and leading grades should be checked, because i suspect ape-index may be positively correlated with in-untero testosterone levels, which might effect boldness as well as physical climbing ability. (NB, girls can have high in-utero testosterone levels without being mannish)
i've just realised that there is actually no particular reason to suppose that long limbs equals long outforce levers within a species, although it is the case between species. but let's not go into that.
in addition to all that i've also just realised that i couldn't give a toss.