This is an excerpt from Therapeutic Stretching by Jane C. Johnson.
There are many reasons for tightness to develop in the posterior thigh. It is commonly reported by runners and people regularly engaged in sports involving the lower limbs, such as tennis or rowing. Shortening of soft tissues of the posterior compartment of the thigh and knee is also likely to occur in people who remain seated for long periods of time, such as drivers, office workers or people who lead sedentary lifestyles. Both active and passive stretches are helpful in combating tight hamstrings.
There are a great many active hamstring stretches to choose from. These range from the simple sitting stretches shown in figures 5.7, 5.10 and 5.26 to standing stretches such as figure 5.11, which increases tension on the posterior thigh by also tensioning the calf muscles. In the supine position the client could use a towel, as in figure 5.28. Bear in mind that dorsiflexing the foot in this way also stretches the calf, and for some clients this may feel uncomfortable.
Remember that the hamstrings are hip extensors, so taking the hip into flexion, as in figure 5.29, will also help stretch these muscles. In this illustration the hamstrings of the right leg are being stretched because this is the hip that has been taken into flexion. Clients with knee problems should avoid this stretch, which places pressure on the knee opposite the thigh being stretched.
Clients who do not wish to do their stretches on the floor could simply try placing one leg on a stool and leaning forward to stretch the hamstrings of that limb. Obviously this is not appropriate for clients with impaired balance.
Less common but arguably just as effective ways to stretch the hamstrings are to apply active soft tissue release as in figures 5.30 and 5.31. Simply provide the client with a tennis ball, and show him how to position it against the thigh (as shown in figure 5.30) and then straighten the leg. The client can move the tennis ball to different positions on the hamstrings in this way, applying this technique for a few minutes each day.
Read more from Therapeutic Stretching by Jane Johnson.