AssaultRunner Pro

A curved manual treadmill for sprint and speed work. There is no motor: stepping toward the front of the curve speeds the belt up and drifting back slows it, so there is no top speed and no waiting for a motor to catch up between repeats. It needs no electrical plug, so it can sit anywhere in a garage or basement, and it takes users up to 350 pounds. It has also been sold as the AirRunner, the name some units carry on the base. It is not an easy-miles machine. The curve takes some getting used to, a steady recovery pace demands concentration, and at about 290 pounds it is hard to move. Expect to pay around $3,000, cheap by curved-treadmill standards but a lot for a second machine.