Why: Reduction in flexibility of the hamstring has been reported to be associated with occurrence of back pain in adolescents and adults in cross-sectional studies.
Start position: Start by holding onto a strong resistance band or towel wrapped around your feet.
The movement: Key here is to attempt to make you low back as straight as you can. If you curl your entire spine- the restriction may be due to neurodynamic mobility deficits than hamstring length.Use the Quad muscles to straighten your knee until you feel a hamstring stretch- this will also help with reciprocally inhibiting the hamstrings.
There are 4 hamstring muscles (2 medial and 2 lateral). To isolate the lateral hamstrings bicep femoris long and short head you can do this by internally rotating your legs so that your toes are pointing together. If your goal is to stretch the medial hamstrings- semimembranosus and semitendinosus then you can externally rotate your legs so that your toes are point out.