Aerobic exercise floor system

A cushioned floor comprising in combination:

• a lower layer of a foamed pad having sufficient thickness and compressive strength that it will always yield when used with static and impulsive loading caused by humans doing exercise on the floor;and
• an attrition resistant upper layer of at least two distinct boards each board comprised of a pair of adjacent contiguous strips, said strips joined to each other by a longitudinal dove tail joint centrally located in said board, said at least two distinct boards having at least one tongue and groove pivoting joint joined with play, said at least one tongue and groove pivoting joint having one lengthwise direction, a slot running parallel to said lengthwise direction of said pivoting joint in alternate strips of said at least two distinct boards, a U-shaped resilient monolithic clip having upright legs inserted into the slots overlapping and asymmetrical to said centrally located longitudinal dove tail joint, one leg of which contains at least one cleat which protrudes away from the directions of the legs and toward a wall of one slot, the combined width of the cleats and the leg inserted in the one slot being wider thus the one slot before insertion into the slot whereby the leg containing said at least one cleat is locked into the slot into which it is inserted thus holding the spring clip in place, the boards being held together by tension in the spring clip, the spring clip being curved in the lengthwise direction between the legs when there is no load on the boards;
• so that when a load is applied and the boards flex, the curved portion straightens so as not to unduly restrain the joint from flexing.