Contrary to popular belief – or the insistence of professional cyclists – shaving your legs doesn’t have anything to do with aerodynamics. In fact, there are no academic studies to show that a bald limb will slice through air any better than a hairy one. The resistance is simply too minimal to matter and, if professional cyclists say otherwise, then it’s simply the placebo effect of feeling and looking like they’re a hardened sportsman (see lurid-coloured lycra, fancy gadgets, having your lunchbox on display etc). That extra mile is all in the mind, after all.
The only genuine reason for body shaving is to reduce road rash, those unfortunate (and sometimes rather gory) moments when a cyclist crashes and has to pick out all manner of grit from their wounds. Having a hairy leg does not make this easy, nor does it make the removal of plasters any less painful.
Before hightech suits were authorised, swimmers had a very good reason to shear their chests smooth due to something called ‘laminar flow’, the ease with which fluid can pass around an object. Water is 1,000 times more dense than air and therefore requires a perfectly smooth surface to cut through it.
Scientific studies have shown that removing body hair dramatically optimizes laminar flow. It can have a great impact on the distance achieved with each stroke and, in an Olympic race, that 100th of a second can make all the difference!