'No more leg days' - Team NZ cyclor's remarkable transformation ahead of 2021 America's Cup

Having adopted a radical new AC75 design for the 2021 America's Cup, Team New Zealand will utilise grinders rather than the cyclors that propelled them to victory in Bermuda two years ago.

For Olympic bronze medal winning cyclist and former cyclor Simon van Velthooven though, the change has seen him have to reshape his body to get ready for the new challenge.

The physical hurt is no stranger to the 30-year-old, now having to make use of his arms as a grinder, after carving out a career with his legs.

"We're institutionalised to pain now and it's just normal," he told 1 NEWS.

"You almost look forward to it, if you don't have a dose of it then you can't really sleep at night.

"It's just all arms, there's no more leg days."

Sports scientist Dan Plews hailed van Velthooven's transformation: "He knows how to go through the right process," Plews said.

"Of course he was blessed with some good genes but that's not enough and he went through the process to get in the shape he's in to become the grinder that he is now."

Previously setting a personal best on the bench press of 80kg, van Velthooven's transformation has seen that nearly doubled, now reaching weights around 150kg. But with the America's Cup creeping closer, van Velthooven is ready to get out of the gym.

"The two hard sessions we have here a week are getting a bit repetitive, and it'll be good to get on the water and watch the days fly by out there."

Team New Zealand are expected to unveil their brand new boat next month, testing their new AC75 on Auckland's Waitemata Harbour.