Athletes with taller, leaner physiques perform better in warmer conditions, study claimsÂ
Short and stocky footballers like may be outrun by taller, leaner athletes such as in the future due to . Meanwhile lanky tennis players like may find they do better in sporting contests when the temperature is hotter. A new study looking at the performance of professional triathletes found men who are taller, with longer limbs, are faster when temperatures are higher. Shorter, stockier men performed better when it was cooler. The new study concludes that people are rather like animals, which tend to be stockier in areas where it is colder, like polar bears, and more lean, like brown bears, in hotter places probably because this better suits the conditions. Analysis was carried out on 173 athletes competing in almost 200 Ironman extreme triathlons over two decades. Tall, lean men were found to be about 2.5 per cent faster when temperatures were higher, compared to short, stocky men, according to the study author, Professor Ryan Calsbeek from Dartmouth University in the US. This is likely because their surface area is larger, so they can dissipate heat from a larger amount of skin, and produce more sweat to cool down. Women also appeared to run faster in hot temperatures when they had longer legs, but not significantly so. This may be because women produce less sweat than men, so that having longer legs to sweat from in hot weather makes less of a difference. The study found a difference only in ultra-running performance, but Professor Calsbeek said the results could apply to other sports. That could mean, as summer football tournaments get hotter, tall and lean footballers like Manchester City star Erling Haaland might do better than short, stocky ones like Wayne Rooney or Lionel Messi. A 2019 study led by the University of Portsmouth, looking at footballers from 1973 to 2014, found the most recent had become taller and more lean. This suggests the muscles and power of players like Alan Shearer are being replaced by the lean, slender physiques of players such as Harry Kane and Marcus Rashford. Professor Calsbeek, whose new study is published in the journal , said: 'People attempting a personal best can think about sporting locations and average temperatures to pick a venue based on whether they are lean and long-limbed or short and stocky. 'These results certainly suggest a lean tennis player like Andy Murray might do better at the warmer US Open than Wimbledon, or a cyclist like Chris Froome might do well if he wanted to take up marathons in warm countries.' The study included triathlons of almost 150 miles in punishingly hot locations like Hawaii and South Africa, and colder countries like Finland and Canada. Peak temperatures ranged from less than 18C (64F) to almost 39C (102F). The research compared athletes' recorded heights and their digitally measured leg and arm length from race photographs. Men were found to be faster at running when temperatures were higher, but not at cycling, which may be less affected by temperature due to air flow, or at swimming, which involves wearing a warm wetsuit even when it is cold. The results back up theories by the 19th-century biologists Carl Bergmann and Joel Asaph Allen, that the overall body size of animals, as well as the length and thickness of their limbs, are linked to their climate. These theories have also been linked to Inuit people being smaller and more compact than Europeans. Professor Calsbeek, a former Ironman contestant himself, was inspired to conduct the study after observing that the three-time winner of the Norseman triathlon, Allan Hovda, was stocky and short. He said: 'I wondered if there was something about body shape that allowed him to do better in the cold and thought about the role temperature might play for this one guy who doesn't look like your standard endurance athlete.' One explanation for Bergmann's rule is that larger animals have a lower surface-area-to-volume ratio than smaller animals, so they emit less body heat and stay warmer in cold climates. A study published last year found that megalodons the species of extinct shark . The authors found that the extinct creature grew to larger sizes in comparatively cooler environments, such as and Peru, than in warmer areas, like in and Panama.