By the time he competed in his second Olympic Games as a sabre fencer in Athens in 2004, Keeth Smart was already a two-time US national sabre champion and the first American to be the top-ranked fencer internationally. But his body was beginning to break down from years of intense training.

“Because of all the weight training I was doing, I had to start taking cortisone shots because I started to develop tendonitis,” Smart says. “A lot of athletes who do high amounts of repetitive weight training have the same issue. Then someone introduced me to an amazing personal trainer, and I started doing resistance training with bands and bungee cords, and that changed everything... I didn’t just get stronger, I got a lot faster, and I recovered from my workouts a lot quicker.”

Smart credits the change in training regimen as a reason for his best Olympic finish in 2008, when he helped lead the US fencing team to a silver medal.

Nearly a decade later, Smart cofounded Physiclo, the world's first performance wear that has resistance built into the fabric of the clothing. After more than a year of research and development, Smart and his team found a level of resistance in the clothing that would work for the greatest number of users. "When you wear the pants, it feels like you are walking up a flight of stairs while you are on level ground." Smart says. "Our internal studes show that when you are wearing the pants, your muscles are working 23% harder than they usually would, and you're burning 14% more calories.