Legs get tight and this stretch helps to loosen them up. Bending your bottom leg will help keep you from arching your back. If placing your head in your hand puts a strain on your neck, rest your head on top of your forearm. Do 1-3 sets, of holding for 15-60 seconds, or six to 12 breaths. Keep in my mind that doing both sides once = 1 set. Enjoy.
This is a good dynamic stretch for warming up the muscles in your hip and thigh. Use a chair for balance. Add a towel, pillow or mat to soften the surface below your bottom knee. Do 1-3 sets of slowly rocking forwards and backwards, 3-4 times per side. Doing both sides once = 1 set.
This stretch is also good if you suffer from back pain. Make sure you keep the knee slightly bent - see picture. You can extend the range of your arms by putting something under your head like a pillow or yoga block. Hold each stretch 30-60 seconds, or for 6 to 12 breaths. Relax your shoulders. Breathe.