Ashley Butterfield Couper is gearing up for the most unusual race of her triathlon adventure, by taking on the Otillo Swimrun World Championship in Sandhamn, Sweden.

Starting on Monday and racing from dusk to dawn, Couper, a six-times Bermuda Half-Marathon Derby winner, will be among the teams of competitors who will have to swim to, and run across, 24 islands that surround the Sandham area, a small settlement in the central-peripheral part of the Stockholm Archipelago in central-eastern Sweden.

The total distance of the gruelling test is 75 kilometres of which 10km are open-water swimming and 65m are trail-running, starting at Sandhamn and finishing at Uto Vardshus on Uto.

To gain entry to Otillo you must either qualify in an Otillo Swimrun World Series race, have great merits, or participate in seven races in 24 months.

It is hardly surprising Estwanik has set her sights on an ambitious endurance race given her family background.

Her mother, Peggy Couper, was one of Bermuda’s top female road runners in the 1980s, uncle Jim Butterfield is an Olympic rower and former triathlete, and aunt Debbie is a multiple May 24 winner.