Designed to be installed in even the most limited spaces, the spas are said to offer a solution for all fitness levels and health regimes, allowing accessible, year-round aquatic exercise.

Optional underwater cameras can be installed to record a swimmer's stroke for easy reviewing in order to help improve performance.

Designed with the input of Phelps, coach Bob Bowman and a team of Master Spas' experienced engineers, the range features six new and different premium swim spas for residential settings and one premium, commercial-grade spa ideal for fitness centres, universities and physical therapy centres.

"One of the biggest goals I have in my career is to grow the sport of swimming in as many ways as possible, and the ability to partner with Master Spas' to create a signature line of swim spas is another unique way to help the sport," said Phelps.

"Our goal with this line of swim spas is to create more and better opportunities for everyone interested in swimming, from exercise enthusiasts through to the next generation of competitive swimmers."

Bob Lauter, chief executive officer of Master Spas, said: "Working with Michael Phelps and Bob Bowman is a once-in-a-lifetime opportunity for us.

"It is a tremendous honour to have this level of input that will draw global attention to the pool and spa industry and help promote the benefits of swimming and aquatic exercise."