As more athletes and individuals who engage in regular physical exercise learn of the benefits of acupuncture both to treat injuries and to enhance their physical activities, acupuncturists are increasingly seeing more musculoskeletal disorders that arise from improper exercise or insufficient stretching. One of the most common of these injuries relates to the hamstrings.

The hamstrings are particularly interesting because frequently, even in those who exercise, they are underdeveloped and tight. Many specific aerobic exercises such as running or walking, and weightlifting exercises such as the squat, tend to work the quadriceps more (although they certainly work on the hamstrings as well). Furthermore, many of the stretches that people practice do not stretch the hamstrings, even if they think they do. Frequently these exercises involve stretching and grasping the feet from either a standing or a sitting position. Most of the time, however, this is done with the knees locked, which takes some of the "stretch" away from the hamstrings. Taken singly or together, these factors contribute towards a propensity for hamstring tension, weakness or even injury, whether at the distal tendinomuscular junction, the origin at the ischium, or in the belly of the muscle itself.

In general, the hamstrings are part of the urinary bladder tendinomuscular channel, though overstrength of the tendinomuscular channels of the gallbladder or stomach might be the cause of hamstring dysfunction. It is also important to realize that dysfunction of the urinary bladder tendinomuscular channel may be a result of imbalance in the three leg yin channels as well.

A good evaluation performed by a qualified provider will indicate the cause of dysfunction or pain. Sometimes injuries are severe and require Western medical treatment. At other times, teaching patients proper stretching and balanced strengthening techniques - or referring out to an appropriate physical therapist or other practitioner if necessary - may significantly help them overcome dysfunction and improve strength and flexibility. Massage, in particular tui na, may be useful as well.

In either case, acupuncture can play an important part in the overall treatment scheme. The choice of local points along with points such as UB40, GB34 and UB36 is easy, and the general "ropiness" of the hamstrings makes it easy to indentify a-shi points and areas of disruption of qi flow. The key to using acupuncture in treating the hamstrings lies in selecting proper distal points that adequately affect the region involved.

I would suggest five distal points (or sets of points) that, through a variety of channel relationships, may prove to be key to affecting the hamstring area, whether used with needles, moxa, or both.

• UB67: The jing-well point of the UB channel, it also affects the entire tendinomuscular channel.
• UB65: The shu-stream point of the channel, it is also the "wood" point channel, and thus also affects the tendinomuscular structure.
• SI1: The jing-well point of the SI channel, it can have a systemic effect on the whole tai yang complex.
• LU6: While this xi-cleft is now commonly used for some types of back pain, it may also affect the hamstrings.
• KI4: The luo point of the kidney channel, this point may be manipulated to remove excess qi from the UB channel complex and "channel" it into more constructive uses.

As has been clear in my previous columns, when dealing with musculoskeletal disorders, my concern is more on the particular effect of a point on a particular individual than with point functions per se. Therefore, in order to evaluate whether these points will be effective on any individual, it is necessary to test them out before needling and to test both contralateral and unilateral points.

My recommendation is to put moderate pressure on the most uncomfortable a-shi point on the hamstrings and test whether pressure on each of these distal points reduces the level of discomfort. You can test each point sequentially. In general, if one or more of these points reduces discomfort by at least 50%, I would consider using it (or them) as distal points. Furthermore, you can check to see whether pressure on distal points along or against the flow of the channel makes a significant difference and needle accordingly. Patients should notice improvement within a few treatments.