If the Dolphins want to match their haul of nine gold, three silver and eight bronze medals at Tokyo 2020, they will not only have to beat the best swimmers in the world, they will also be battling another formidable foe – the water’s drag.

Generating immense power is essential to swimming fast, but overcoming the resistance of drag is equally crucial for victory. So, why is it a problem, and what should you look for in the race for gold?

This photo of Kaylee McKeown at the Australian Swimming trials last month shows us where drag is visible in a race. The pressure of McKeown’s head pushing into the water forces the water up into a wave in front of her, which takes energy from her and slows her down. This is something that affects all swimmers.Credit: Getty Images

Water is a drag because it’s so dense. And this drag slows swimmers down,........

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