Knit picking

Get woolly for maximum gains

It’s an oldie but a goodie: a paper in 1979 on the influence of muscle temperature on performance concluded that across a range of 30°C to 39°C (that is, the temperature of the muscles, not environmental temperature), exercise performance improves 2-5% per 1°C rise. In other words, the colder your muscles, the worse you perform. That’s why warming up and staying warm is so imperative. But how do you keep warm in the cold?

According to a more recent paper published last September, titled Practicing Sport in Cold Environments, fabrics play a crucial role. The paper suggests fabrics should have: ‘(1) Good “ease of wicking action”, (2) a high “rate of drying”, (3) a high capacitance for “moisture regain (the amount of moisture a material can absorb before it feels cold)” and (4) “the degree of insulation a material loses when it becomes wet” should be low.’ And what material does these things best? Our old friend merino wool. ‘Merino-based wool fabric when worn against the skin has greater thermal insulation properties and water absorbency than synthetic underwear,’ claims the 2021 study. It cites evidence from another paper investigating fabrics on performance that showed merino wool fabric to have 14% lower air permeability, 6% lower water vapour permeability, to absorb 60% more water and to offer nearly twice the thermal resistance as polyester – the greater the thermal resistance, the lower a material’s heat loss.

Outer layers, though, were still crucial. Merino has the ability to draw water from the skin, but that water needs to dissipate before it becomes cold and so counterproductive to muscle warmth. As such, merino may well work best as a base layer paired with ‘subsequent layers that are insulative and highly breathable to water vapour’. Time to get those merino sheep some Gore-tex onesies.