On earth we face a different challenge: weak bones due to inactivity. Yet, a nearly $6,000 treadmill is gaining popularity even though it's motor free.
"The challenge with treadmills is they ramp up and they ramp down at a much slower pace than an athlete would move at," said Weber. "And so we worked very hard on trying to figure out a way to accommodate an athlete's movement pattern."
Conventional treadmills have a belt stretched across wood which makes the running surface hard, and that can strain joints, muscles and tendons. But the new curled design relies on cushioned slats only, yet withstands 800 pounds.
"Having a treadmill that already has a slight incline to it is already forcing that athlete to land on the ball of their foot," said CrossFit coach Carl Borg.
This ensures proper running technique. But this machine isn't for the autopilot crowd that reads or watches TV, it goes as fast or as slow as you go, which requires your full attention.
And if you can't seem to find time to get to the gym - don't, your work station can become a workout station with a desk treadmill.
"I have it built in underneath my desk and it is available for me to use whenever I want to," said attorney Scott Turner.
Turner walks four miles a day. He types, texts and even conducts conference calls while walking a mile an hour to keep his blood moving.
"I do it to stay relaxed. I do it to increase my stamina, increase my productivity," said Turner.