great for muscle recouperation. post-injury. >> i tried it for the first time and i just loved it. >> i normally run on the under water treadmill. i have water heavyweights i can use, i can work out my arms at the same time. >> we have this weightless dumbbell here. however, under water, it becomes a weighted dumbbell. so as you are running on the treadmill, you can do -- you can use these dumbbells and in a swinging motion. you can do dumbbell curls and you can do some solar presses. when i get in here i can still do my running on the treadmill. and still >>> for 80 kids in prince george's county today, santa came early and wore a badge. as derrick ward reports, the special youngsters were treated to a mini shopping spree and what makes the sleep number store different? the sleep number bed. with the sleep number bed, it's not about soft or firm. it's about support where you find it most comfortable. the magic of this bed is that you're sleeping on something that conforms to your individual shape. on a traditional