Olympic silver medalist Michael Jamieson prepared for his swim by sleeping in an altitude chamber in his bedroom, it has been disclosed.
Fellow finalist and Team GB swimmer Andrew Willis also used the tents, which trigger the body to create more oxygen to fuel training. Steve Baddley, director of sport at Team Bath, said the pair, who were both making their Olympic debuts, had used the unusual method while training at Bath ITC.
"They've been set up in the bedrooms," Mr Baddley told BBC Radio Bristol.
"One was sleeping at 2,800 metres and another at 2,400 metres. It's used to thin their blood out and increase the red blood cell count and get themselves in top condition.
"It's a positive rivalry which has taken them to greater heights."
Mr Baddley said the two swimmers used the unusual method rather than train in a pool at altitude.
"It sounds slightly quirky but the coach said that whether it works physically or mentally, I doesn't matter. If they believe in it, then that's the main thing," he said.
In Wednesday's 200 metres breaststroke final Glasgow-born Jamieson produced the fourth fastest swim in the event's history to claim silver.
The 23-year-old Bath University sports performance student enjoyed a shoot-out down the final length with Daniel Gyurta which drove the Hungarian to set a new world record of two minutes 07.28 seconds, Jamieson just 0.15secs adrift. Jamieson's team-mate Willis was eighth in 2:09.44, despite having qualified third in an English record of 2:08.47.
Athletes have long been training at high altitudes to try to increase endurance levels. In 2006, the World Anti-Doping Authority (WADA) decided not to ban altitude machines even though there are benefits without effort, and the hypoxic chambers are now being installed outside of training centres.