The overall rowing experience encompasses pulley, seat, and — of course — resistance. Air and water have very distinct qualities, making them impossible to compare but interesting to contrast. Air stores inertia, which feeds into intense, constant effort during a goal-oriented workout. Water’s more sluggish drag makes for demanding exercise, but one that’s less consistent.
The frame is beyond durable and is designed for absorbing sound and vibration. There’s no creaking or other sounds that you might expect from wood components. It has a low center of gravity that keeps the rower in place while exerting full rowing power. The polycarbonate water tank is equally durable and practically indestructible. The Classic Rower doesn’t have any moving parts that can wear out, or belts and pulleys that need to be maintained.
The rowing machine itself is unlike any other on the market with its patented water filled flywheel. It is hard to exactly copy the action of a scull on the water, but the mechanics of the flywheel spinning in water comes in a close second on dry land. The fact that the water is 800 times denser than air means that there is no need for any extra resistance or dampening that you will find in normal air rowers. The faster you pull, the more resistance is generated giving it infinite variability. However, if you want to be able to practice rowing with a faster stroke, you will have to reduce the amount of water in the tank unlike an air rower where you just have to adjust the baffle.
From a fitness perspective, the WaterRower Club 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.
* While there is nothing to adjust from row to row on the WaterRower, it is possible to increase or decrease the level of resistance by changing how much water you put in the drum. The monitor is pre-calibrated to match 17 liters of water, but you can change that if you want. More than 17 liters = more resistance, up to the max fill line. This is not something you'll want to change frequently, it's more of a set-it-and-forget-it thing.

Rowing has long been recognized as the perfect aerobic pursuit, with naturally smooth and flowing movements that don't tax the joints but do boost the heart rate. Now you can take your rowing experience to the next level with the WaterRower Natural rowing machine. Using the same principles that govern the dynamics of a boat in water, the WaterRower Natural is outfitted with a "water flywheel" that consists of two paddles in an enclosed tank of water that provide smooth, quiet resistance, just like the paddles in an actual body of water. As a result, the machine has no moving parts that can wear out over time (even the recoil belt and pulleys don't require lubricating or maintaining). More significantly, the water tank and flywheel create a self-regulating resistance system that eliminates the need for a motor. As with real rowing, when you paddle faster, the increased drag provides more resistance. When you paddle slower, the resistance is less intense. The only limit to how fast you can row is your strength and your ability to overcome drag. And unlike conventional rowing machines, which tend to be jerky and jarring, the WaterRower Natural is remarkably smooth and fluid.