Tuesday, November 3, 2009

Injury and the running man theory

John Hawkes quite reasonably asked for critiques of Lieberman and Bramble's "endurance running" hypothesis that persistence hunting was a significant factor on the evolution of the various functional systems that contribute to endurance running, and asked, if humans evolved to be long distance runners, why are we so prone to injury? I don't think we have enough data to ask this question, that is, are we prone to injury?
1. Injury rates may be high because racing and the training required to race (intervals, tempo runs) stresses the musculoskeletal system well above any safety factor that evolved in response to persistence hunting. High injury rates among racers, then, may not be relevant to the hypothesis.
2. I did a quick google scholar search of injury rates among race horses and found "fractures and tendon injuries in National Hunt horses in training in the UK: a pilot study" published in the Equine Veterinary Journal. The authors found that 25% of the National Hunt race horses sustained either a fracture or a tendon/ligament injury during a single race season. Should we conclude from these high rates of injury that horses didn't evolve to run?
3. What we need are injury rates among runners persistence hunters. Or at least populations that run long slow distance and only LSD. I'm not aware of any of the injury studies that decompose the data in this manner. And anecdotal stories about the tarahumara isn't data. But even the relevance of these injury data collected from people raised on concrete and cars is questionable.
4. I'd also be interested in chronic injury rates among endurance mammals such as wolves or wildebeest.
5. As with any evolved response, trade-offs occur. What is the fitness cost of plantar fascitis or IT band syndrome?