WEBLower Extremity Strengthening Home Exercise Program. Closed Chain, Standing. 1. Quadricep Set (quadriceps are the front thigh muscles): Standing. 1. Heel strike — leg forward, ankle bent, heel contact, tighten quad . 2. Midstance — with slight bend in knee and foot flat on the floor, tighten quad . 3. Heel off – leg behind, heel off floor,