Abstract: To support a deck of an exercise treadmill one or more arcuate leaf springs are used in a deck support structure. The leaf springs can be made of a single member of elastomeric material. An adjustment mechanism can be used to changed the radius of the leaf springs in order to vary spring rates of the leaf springs. Where a number of different leaf springs are used, the adjustment mechanism can be used to adjust the spring rates of different springs independently.

Abstract: In an elliptical step exercise apparatus where stride length can be varied the various user programs can take advantage of this feature to provide for an enhanced workout. A control system can be used to implement a preprogrammed exercise routine such as a hill program where stride is shortened as the user goes up a simulated hill and lengthened as the user goes down the hill. In an interval training program, stride length can be increased and decreased at periodic intervals. In a cross training program, stride length can be decreased when the user is pedaling backwards and increased when the user is pedaling forwards.