He said Sir Ranulph would have been tired after the endurance run but "he is, by any measure, no ordinary man in terms of his achievements and stamina".

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Over time ladies were encouraged to save their best dresses for the Gold Cup, the prestigious endurance race run on the Thursday and won in 2015 by Trip to Paris.

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Since that time, I train regularly and run in various types of endurance races.

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His rowing companion Mr Humphreys, 32, from Clapham, London, previously spent four years cycling round the world, has written two books and run the Marathon des Sables, a six-day endurance race across the Sahara desert.

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Science shows that peak performance in endurance athletics tends to occur either at negative or even splits, which happens when athletes start out slow enough to run the second half faster and the finish faster still.

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