Confessions of a Quackbuster

This blog deals with healthcare consumer protection, and is therefore about quackery, healthfraud, chiropractic, and other forms of so-Called "Alternative" Medicine (sCAM).

Sunday, January 09, 2005

Low Back Pain, Short Hamstrings, and Straight Leg Lifts

The following is an email I sent to the Supertraining list before the death of its moderator, Mel Siff, PhD, a man of high integrity and great knowledge. His passing was a sad day for many.

In it I propose some theories and ask some questions. I hope that some readers here can shed more light on these subjects.

Subject: Re: [Supertraining] Leg Lowering Test for the Abdominal Strength

Hi Mel,

Here are a couple things somewhat related to this discussion I wrote during some discussions on the Healthfraud list. I would like to learn more on this subject. I've asked for supplementary information before, and gotten no response. But you're an expert in this area. What are your thoughts on what I've written below?

(Just a note. The subject line above deals with leg lowering, while what I've written deals with leg raising. While in practice there may not be much difference - what goes up must come down! - the fact that muscle strength is greater in excentric work than concentric, increases the risk of overloading and muscle injury (below I deal with disc injury). That's why I usually recommend that my patients do the concentric slow, and the excentric fast. Of course there are certain top athletes that need to train excentrically. While the risk is greater, it's their life. They may well be strong enough to tolerate it, but it can't be recommended for ordinary people, especially patients. The "Double Leg-Lowering (DLL) test" (I haven't read the article yet) would be more of a test of the iliopsoas muscles, than the abdominals. Since the abdominals aren't hip flexors, they only tense up to stabilize the pelvis, enabling the iliopsoas to do their job.)


Western civilization, with its wide-spread use of chairs in the sitting position, is also afflicted with LBP. A possible mechanism connecting the two is here proposed. Whether this connection is legitimate is worth investigating. In fact, it may already have been!

The sitting position here referred to is one with 90 degree flexion in both the hips and knees, as well as a straightening out of the lumbar lordosis. The habitual use of this position a significant amount of the time, both at work and in leisure time, results in an adaptation to this position by the muscles, ligaments, joint capsules, blood vessels and nerves which pass and surround these joints.

The primary structures that can give trouble in the back are the hamstrings, sciatic nerves and iliopsoas muscles. Other structures can also be affected. Many of these affected anatomical structures become unnaturally shortened, thus negatively affecting the way they influence the range of motion (ROM) during movements of the back, hips and knees.

During flexion this results in an unnatural and unfortunate increase in loading of the paravertebral musculature, beyond that which they would normally experience, were the affected anatomical structures of normal length. This loading works directly on the discs.

The shortened hamstrings stop the forward tipping of the pelvis, letting the lower back take over the work of bending forward, by causing it to first lose its lordosis, and then actually beginning to bend forwards in a kyphosis. This has the unfortunate effect of moving the center of rotation for flexion of the trunk from the hip joints up to the 4th and 5th lumbar vertebra. The resulting asymetrical loading puts an unusually large degree of pressure on the anterior portions of the discs and stretches the posterior portions, contributing to eventual failure and herniating of the lumbar discs.

The shortened iliopsoas muscles have the effect in the standing postion of pulling the lumbar spine in an anterior direction, thus increasing the lumbar lordosis more than necessary. The fact that the psoas major muscles have their upper insertion directly on the sides of the lumbar discs means that there is an increased pull on them. Whether this is injurious is a good question.

The shortened sciatic nerves can become tightened during forward bending with straightened legs (the same effect as straight leg raising (SLR)), resulting in sciatic pain. There can also be other symptoms of abnormal neural tension (ANT).

In persons without an unnatural shortening of the hamstrings, it is possible while standing to bend forwards all the way with straight legs, so as to have the head hanging down in front of the lower legs, without totally losing the natural curves of the spine. This actually has a traction-like effect on the lower back, which can actually have a therapeutically beneficial effect. The same position can be taken while sitting on the floor. This ability should not be considered abnormal when examining for hypermobility. It should be considered normal.

In certain cultures (Asian, African, Eskimo - I've lived and worked in Greenland) where the use of chairs is/was not customary, and where sitting on the floor is (or has been) the norm, it is common to see the ability mentioned above. Whether these people have less LBP, and whether that is a result of the disuse of chairs, is a question I'd like to get answered.

In these modern times of ergonomic thinking, there have been attempts to design aids to lessen LBP. Foam rubber sitting wedges and balance chairs (Norwegian kneeling chair) are, in my opinion, very short-sighted attempts, that actually contribute to the problem. They attack the problem by choosing positions which avoid straining the already shortened structures. This happens by choosing positions that actually allow even more shortening, instead of attacking the problem by adopting habitual postures and treatments that result in stretching things to what should be their normal length.


Just some added information (from a cautionary angle).

Straight leg lifts can easily cause groin pain, and should not usually be used as a treatment for such pain. The exercise causes extreme loading of the iliopsoas muscle, which has its lower attachment in the groin, specifically the lesser trochanter of the femur. It is a muscle that is also used a lot when doing cross-country skiing. As in any case of muscle soreness or injury due to excessive use, the first line of treatment is avoiding the type of loading that caused the injury, IOW, take it easy for awhile. Later, when the pain is gone, careful strengthening can then be used to prevent further injury. It's a matter of balancing the amount of strength the muscle has, with the load it usually gets. If the muscle is strengthened, it can then tolerate the same load much easier (kind of like adding a fifth gear to a four gear transmission). Increasing the strength is equivalent to decreasing the load.

Straight leg lifts, especially with boots on (military basic training torture), has far too many down sides to be worth doing. It should be reserved only for extremely well trained athletes who need the specific training it gives, and who don't have any form of back trouble. It puts an extremely high load on the lower back.

I'd really appreciate getting some info from anyone who has some numbers on how many pounds of pressure are placed on the discs of the lower back at specific angles and weights.

Here is a picture of the muscle: