The concern, he said, was not so much the wrist as the side and hamstring muscles that have been underused.

Don't lean forward from the waist - it will lessen the involvement of the hamstring muscles - or backwards.

There are three hamstring muscles down each leg, one going to the outside, the others to the inside of the leg, but all attaching at the knee joint.

Tight hamstring muscles are often considered a risk factor for back pain, but are more likely a symptom than a cause.

The hamstring muscles activate in mid-swing phase to help decelerate the lower leg.