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Short and stocky footballers like Lionel Messi may in the future be outnumbered by taller, slimmer athletes like Erling Haaland due to climate change.
Meanwhile, lanky tennis players like Andy Murray may find they do better in sporting competitions when the temperature is warmer.
A new study of the performance of professional triathletes found that men who are taller, with longer limbs, run faster when the temperature is higher.
Shorter, stockier men performed better when it was cooler.
As summer football tournaments heat up, tall and lean footballers like Manchester City star Erling Haaland (right) may fare better than short, stocky footballers like Wayne Rooney or Lionel Messi (left)
The new study finds that humans are a bit like animals, which tend to be stockier in areas where it’s colder, like polar bears, and leaner, like brown bears, in warmer areas — probably because it’s more suited to the conditions.
An analysis was conducted of 173 athletes who competed in nearly 200 Ironman extreme triathlons over two decades.
According to the study’s author, Professor Ryan Calsbeek of Dartmouth University in the US, tall, lean men were found to run about 2.5 percent faster when the temperature was higher, compared to short, stocky men.
This is probably because their surface area is larger, which allows them to dissipate heat from a larger area of the skin and produce more sweat to cool down.
Women also seemed to run faster in high temperatures if they had longer legs, but not significantly.
This may be because women produce less sweat than men, so having longer legs to sweat from in hot weather matters less.
The study only found a difference in ultra-running performance, but Professor Calsbeek said the results could apply to other sports.
That could mean that, as summer football tournaments get hotter, tall and lean footballers like Manchester City star Erling Haaland might fare better than short, stocky footballers like Wayne Rooney or Lionel Messi.
A 2019 study led by the University of Portsmouth, which looked at football players from 1973 to 2014, found that the most recent had grown taller and slimmer.
This suggests that the muscle and strength of players like Alan Shearer are being replaced by the lean, lean physique of players like Harry Kane and Marcus Rashford.
A lean tennis player like Andy Murray (pictured) may fare better at the warmer US Open than Wimbledon
Professor Calsbeek, whose new study has been published in the journal PLOS Onesaid: ‘People trying a personal best can think about sporting venues and average temperatures to choose a venue based on whether they are slim and long-limbed or short and stocky.
“These results certainly suggest that a lean tennis player like Andy Murray might do better at the warmer US Open than Wimbledon, or that a cyclist like Chris Froome might do well if he wanted to run marathons in warm countries.”
The study included nearly 150-mile triathlons in scorching hot locations such as Hawaii and South Africa, and colder countries such as Finland and Canada.
Peak temperatures ranged from less than 18°C (64°F) to nearly 39°C (102°F).
The study compared athletes’ recorded heights and their digitally measured leg and arm lengths from racing photographs.
Men were found to be faster in running when the temperature was higher, but not in cycling, which may be less affected by temperature due to airflow, or in swimming, which requires a warm wetsuit to be worn even when it’s cold.
The results support theories by 19th-century biologists Carl Bergmann and Joel Asaph Allen that animals’ total body size, as well as the length and thickness of their limbs, are related to their climate.
These theories have also been linked to the fact that Inuit people are smaller and more compact than Europeans.
Professor Calsbeek, himself a former Ironman competitor, was inspired to conduct the research after noticing that three-time Norwegian triathlon winner Allan Hovda was stocky and short.
He said, “I wondered if there was something about his body shape that made him do better in the cold and thought about the role that temperature might play for this one guy who doesn’t look like your standard endurance athlete.”
Scientists have also long known that some species are smaller in warmer parts of their habitat — a pattern called “Bergmann’s rule,” named after 19th-century German biologist Carl Bergmann (pictured)
One explanation for Bergmann’s rule is that larger animals have a lower surface-to-volume ratio than smaller animals, so they give off less body heat and stay warmer in cold climates.
A study published last year found that megalodons – the species of extinct sharks – grew even bigger in colder waters.
The authors found that the extinct creature grew larger in relatively cooler environments, such as North Carolina and Peru, than in warmer regions, such as Florida and Panama.