An exercise support structure includes a knee support having a tiered recess with a bottom wall, a lower circular tier, and an upper egg-shaped tier; and a wrist support having a tiered support structure with a bottom wall, a lower egg-shaped tier and an upper circular tier, where the knee support and the wrist support are complementary in shape and are interfittingly received in mated relation to form a block. The edges of the tiers may be beveled, forming a smooth transition therebetween. The structure may be made from a soft, durable resilient material, such as foam, silicone gel, rubber, synthetic rubber, or organic tree sap.