US Patent 7238148 Force swing exercise apparatus

An exercise apparatus comprises a frame having a base and an apex. A least one pivot is connected to the frame for supporting a swinging arm. The opposite end of the arm supports a seat for an exercising athlete, and optional weights. The frame supports a force plate opposed to the seat. The seat and the force plate are connected by elastic members, such as bands, that bias the seat toward the force plate. The athlete develops reversal strength by extending his legs to bound from the force plate, then stopping the resulting forward motion at a predetermined joint position before rebounding again.