. >> reporter: former baseball player max gilbert suffers aches and pains when working out. a different kind of impact training using treadmill under water that you're basically using all of your extremities. you're fighting against the treadmill to see what you can get out of your body. >> reporter: the motion mimics running on dry land. russ romano is the head. >> you can work with three planes of motion, work forward, laterally. you can run, jump, do lunches. >> reporter: muscles can work through water. the higher the water level, the less impact on your joints and that allows for more pain-free movement when you're rehabbing from injury. >> your knee joint is only seeing 25% of the force versus 100% of your full body weight. >> reporter: doctors say athletes and patients with sports injuries can recover months and even weeks faster. it also helps with those with arthritis. gilbert needed just 15 minutes to get a workout. >> i'm tired. toinlt know if you can tell. i'm pretty beat. >> reporter: without the soreness. danielle nottingham, cbs news, los angeles. >>> coming up