The habit of tucking your pelvis under to relieve back pain, wearing high heels and simply carrying extra pregnancy weight can tighten your hamstring (rear thigh) muscles. Stretching these large muscles will create space in your knee joints and help ease tension in your legs.
Standing barefoot, bend forward to place your hands flat on the seat of a firm chair. Slowly straighten both legs. If your hamstrings are very tight, your spine will round up like a mountain. Allow your pelvis to untuck, creating a natural lumbar curve, or “valley,” in your spine [shown]. The tighter your muscles, the more you will feel this down the backs of your legs.