Side bend
Principally a latissimus dorsi stretch as shown, but also stretches spinal muscles and helps improve flexibility around middle and lower spine. Simply lean over to one side with the opposite arm above the head. Three times each side, held 10-20 seconds. Note that if your lower back and abdominal muscles are not toned up, this can be a tricky position to return from; if that's likely, use the free hand (the one on the hip in the picture) for support (for example, on a low wall, table or chair back). There are some useful - variations on this exercise to focus on different muscles.
Variations: Top

 To work more on the waist and less on the the upper body, keep both hands on hips and allow the body to bend further. But remember not to go beyond your capability to get back safely, and if necesary use a support with the free hand so you can push yourself back up.

 To stretch the latissimus dorsi more, tilt the body to the side a little (pretty much as the picture shows) and extend the arm upwards. This is also less likely to overextend the lower back.

Back Back | Top