Manual Curve Treadmill
How Does a Curved Treadmill Work?
The mechanical secret of curved treadmills is a mix of gravity, friction, and exploration of the forces during running. During the downstroke backwards, the foot and weight of the body literally pull the tread down and back, and this happens because of the curved shape of the equipment. The point of contact is significantly ahead of the center of mass; thus, the experience of support is different than with other non-motorized treadmill options, or running on the ground.
The differences, while not highly visible to the naked eye, are enough to help slightly deload the body with vertical ground reaction forces. Running on the curve may help some athletes or fitness users reduce the stress on their legs from vertical ground reaction forces. However, because curved treadmills are designed uniquely, measuring forces on them is a difficult process because force plates are usually large and obviously flat.
The key to a good curved treadmill is the ball bearings or ability to reduce horizontal friction of the early part of foot strike to reduce artificial changes to the firing pattern. Ideally, the the less friction there is earlier during foot strike, the more the muscle firing pattern will improve, but a tradeoff exists because a braking phase is a necessary evil for propulsion. Technically, at top speed you use very little horizontal force contribution, as most of the speed is generated by redirecting vertical force, but submaximally the hip uses horizontal forces in running locomotion. The debate about what is more important for speed has cooled off, as recent research clearly points out that a balance of all three forces—lateral, horizontal, and vertical—is necessary for sprinting success. Using a curved treadmill is very similar to overground running, but it’s far from interchangeable.