Start-up Black Box VR has developed a full-body workout in the form of a 30-minute virtual reality experience.
It uses a bespoke resistance training machine and an HTC Vive headset. The entire set-up is about the size of a family bathroom.
It is one of several innovations at the CES tech show in Las Vegas to propose mixing VR and fitness training.
But one expert said the firm would need to address safety concerns for the idea to be a success.
The Idaho-based firm's solution involves participants entering a virtual arena, where they compete against an avatar and, eventually, one another.
The firm's founders, Ryan DeLuca and Preston Lewis, were also behind the successful fitness empire bodybuilding.com.
Exercise and repeat
Black Box VR's business plan is to open boutique gyms across the US, in which each member will enter their own "black box" space for the gamified work-out, which will track their progress.
An at-home version of the equipment could be developed in the future, the firm said.
"Most people stop going [to the gym] after a couple of weeks so adherence is something that's a critical factor of what we're trying to solve," general manager Jim Bradbury told the BBC.
One VR-industry watcher said the idea had potential, but had concerns.
"Human beings in general find it hard to retain the habit of exercise and there's been many attempts to try and make it more appealing - so, VR makes sense from the perspective of trying to make the gym less boring," said J P Gownder from the consultancy Forrester.
"But the cost of the equipment is going to make it an expensive get-up.
"And will it be safe enough for people to use?
"I'm not aware of the Vive having been stress-tested for this kind of use, and [Black Box VR] is going to need to prove that it has taken account of impact on the body of using the headset during strenuous exercise."
Job Stauffer, a games developer who now works with the VR Health Institute - who is helping Black Box VR with promotional activities at CES - says he has personally benefited from virtual reality.
He told the BBC he had lost more than 82lb (37kg) playing such games in addition to improving his diet.
"Late in 2016, I was probably the unhealthiest I'd ever been in my life, well over 300 pounds," he said.
"And I started playing games on HTC Vive and Oculus and I started to notice that wow, like I'm sweating I'm getting the best workout I've ever had."
Mr Stauffer said he started by playing the indie game Sound Boxing, which he described as "Guitar Hero for the arms".
He said he then moved onto Space Pirate Trainer, which he compared with using an elliptical machine - or cross-trainer - in terms of calories burned.
The VR Health Institute is now developing a Pan European Game Information (Pegi)-style rating system for games to grade them according to their activity level, he added.
"A lot of people in the games business work an incredible amount of hours and often don't get the time that they need to take care of themselves," he said.
"At the same time playing games is a sedentary experience but VR changes all of that - that room-scale experiences are engaging your body in full."
Virtual reality and fitness is a small but growing market.
At last year's CES a firm called Icaros showed off a cradle that simulated flight while giving users a work out as they planked their way across a mountain range.
At this year's event a Czech start-up, Sense Arena, is promoting the use of VR to train athletes to play ice hockey, basketball and football. It suggests the tech could ultimately lead to fewer injuries during matches.
Meanwhile at the VR Fit gym in Columbus, Ohio, members can already work out with a virtual reality personal trainer for $60 (£44) per session.
By Zoe Kleinman, Las Vegas
In my two-minute demonstration, I chest-pressed my way to victory in front of a crowd in a huge virtual arena, punching out bowling balls of fire and, inexplicably, large green birds as I pulled the machine, with more resistance piling on at every repetition.
I was rewarded with a virtual sweat band in a prize box and aching biceps for the rest of the afternoon.
There was no noticeable latency between my action and the action I saw in VR, and the graphics, while a bit strange, were immersive. It certainly beat watching rolling news programmes in the gym with the sound down.
The demo appears to have been designed with male testers in mind - the reps were heavy, and the only available profile to compete against was a macho avatar called Razer wearing green armour.
But the firm was at pains to point out to me that ultimately people could compete against each other, and that other computer-based avatars would also be developed.
Of course the concept of getting fit while playing a game is as old as sport itself, and Black Box has been developed by people who are already very motivated by fitness.
After my brief experience I couldn't say whether it would hold my attention in the long run. But on the other hand, neither has my gym membership.