The water flywheel is comprised of two paddles encased in an enclosed tank of water. As you pull the cable, the paddles move through the water creating resistance. The beauty of this machine is it uses the mass/density of water. The paddles create the drag, so the harder you pull, the more resistance increases. Think about moving your hands through water. The faster you go, the more dense water feels. The slower you go, the less you feel the resistance. And this type of resistance is excellent for your joints. Click here to read the full review.
However, I own an air rower and have zero worries about maxing out it’s ability. I can completely exhaust myself on any type of workout. Air and water rowers are the chosen resistance type by Olympic athletes and any athlete looking to train their full-body cardio. I don’t think they would choose this resistance type if they felt they could max it out.
From a fitness perspective, the WaterRower Natural works 84 percent of your muscle mass, helping tone and strengthen your muscles while burning far more calories than most other aerobic machines. The exercise is also low impact, as it removes all the body weight from the ankles, knees, and hips, but still moves the limbs and joints through a full range of motion--from completely extended to completely contracted.