Slump stretching for low back and leg pain

Cleland JA, Childs JD, Palmer JA, Sarah Eberhart S. Slump stretching in the management of non-radicular low back pain: A pilot clinical trial. Manual Therapy 11 (2006) 279-286

This study was performed to assess the additive effect of slump stretching on patients with low back and leg pain, with the idea that patients who received slump stretching in addition to a standard physical therapy plan would have greater improvements in disability, pain, and centralization of symptoms than patients who received standard care only. Subject were 30 people between 18 and 60 years of age with a chief complaint of LBP referred to physical therapy. Patients were required to have symptoms that referred distal to the buttocks, reproduction of the patient’s symptoms with slump testing, no change in symptoms with lumbar flexion or extension, and a baseline Oswestry score greater than 10%. Exclusion criteria included positive neurologic signs or symptoms suggestive of nerve root involvement (diminished upper or lower extremity reflexes, sensation to sharp and dull, or strength), osteoporosis, or a straight leg raise (SLR) test of less than 45 degrees. Eighty-one patients (69%) did not satisfy the inclusion and exclusion criteria for the study.

All patients completed several self-report measures including a body diagram, numeric pain rating scale (NPRS), and the modified Oswestry Disability Index (ODI). Fourteen patients were randomized to receive lumbar spine mobilization and exercise, and 16 received lumbar spine mobilization, exercise, and slump stretching. All patients were treated in physical therapy twice weekly for 3 weeks for a total of 6 visits.

Slump stretching was performed with the patient in the long sitting position with the patient’s feet against the wall to assure the ankle remained in 0 degrees of dorsiflexion. The therapist applied over pressure into cervical spine flexion to the point where the patient’s symptoms were reproduced (Fig. 2). The position was held for 30 s. A total of 5 repetitions were completed.

At discharge, patients who received slump stretching demonstrated significantly greater improvements in disability (9.7 points on the ODI), pain (.93 points on the NPRS), and centralization of symptoms than patients who did not. The results suggest that slump stretching is beneficial for improving short-term disability, pain, and centralization of symptoms.

I absolutely love this study. It represents a lot of what I like about some of Josh Cleland’s work – it asks a straightforward clinical question that has been generally accepted but not formally tested in the physical therapy world, and then sets up a trial that involves treatments with strong external validity. Many studies answer such specific questions that it is hard to take the information straight to the clinic. This study is different, because if you have a patient who fits the criteria outlined above – leg pain, not changing with lumbar flexion and extension, no neurologic symptoms and, generally, fairly well-controlled symptoms – you may be missing something if you are not adding slump stretching to that patient’s treatment. I found it especially interesting that the authors found increased centralization over time, as I had not read of or seen that previously in relation to slump stretching.

The one problem that I have with this study comes from my background in McKenzie training, and is an issue that often comes up with the type of repeated motion testing performed in this study and those carried out by Cleland, Childs and others. The patient group that was treated here would be analogous in diagnosis and treatment to McKenzie’s adherent nerve root – intermittent leg pain, produced with tension on the nerve, but otherwise painfree in the leg. This diagnosis is only arrived at after exhaustive repeated motion testing, and is probably found in 2-5% of patients, versus the 31% of patients in the current study. Given that the repeated motion testing was not specifically described in this paper, it would be interesting to see if more subjects would have been excluded with different repeated motion testing. Perhaps the results would have been even stronger.

Does muscle stretching stretch muscles, or do we just get used to it?

Folpp H, Deall S, Harvey LA and Gwinn T  Can apparent changes in muscle extensibility with regular stretch be explained by changes in tolerance to stretch? Australian Journal of Physiotherapy 2006: 52. 45-50

I’m always interested in studies that address stretching, because it seems that nearly every patient with an orthopedic ailment expresses guilt that they don’t stretch enough, or they do the wrong stretches, and that they know that (insert individual ailment) would be better off if they would just stretch more. Hamstrings seem to be especially culpable – everyone has been told by their friend, doctor, or personal trainer that if their hamstrings were looser, they wouldn’t have their back pain. It’s remarkable, because it comes even from people with excellent flexibility. While there is very good evidence that applies to many people regarding the negative effects of sustained postures, especially on the spine, and the benefit of frequent position change, there is very little evidence for the benefit of standard stretching in preventing injury or increasing performance (although yoga is gaining evidence as a treatment for chronic low back pain). If anything, static stretching has been shown to decrease performance in activities requiring power, such as vertical leap.

Given that caveat, there are people for whom there are benefits to stretching, such as gymnasts and ballerinas, or hurdlers, who require muscular flexibility to perform their sports with good form and efficiency. This study went beyond looking at ways to increase hamstring flexibility, which is what is performed in most flexibility studies, and focused on the mechanism of change. They did this by differentiating between muscle extensibility, which was the motion achieved with application of a standard external torque, and stretch tolerance, which was motion achieved with the subject’s maximum tolerated torque. They used 20 subjects, average age 24, with “tight” hamstrings (unable to put their palms on the floor in standing) but otherwise free of back, hip or knee pathology. Hamstring flexibility was measured in supine, with the knee locked in an full extension with a brace, and rotated through use of a wheel with weights to produce rotation, which was centered at the hip joint. To test muscle extensibility, a standard load was applied to the leg, and the degrees at the end of three minutes was used. In assessing stretch tolerance, weights were gradually added in a standardized manner until the subject reported that they could not tolerate any further stretch. All subjects were randomized to have one experimental limb and one control limb; the intervention on the experimental limb involved performing a 20-minute seated hamstring stretch five times a week for four weeks. Four of the five weekly stretch sessions were supervised, and the subjects generally had excellent compliance.

After the intervention, the intervention and control limbs were retested. There were almost no changes in motion in any aspects of testing in the control limb. In the experimental limb, the increase in motion with the standardized torque was –1 degree (95% CI –4 to 3 degrees), while the change in motion with the maximum-tolerated torque was 8 degrees (95% CI 5 to 12 degrees). It’s interesting that a P value wasn’t reported, but the difference in 95% confidence intervals indicate the significance of the difference. This increase in tolerated stretch was matched by the increase in the torque tolerated by subjects of 12 Nm (95% CI 7 to 18 Nm).

The authors describe these results as supporting the idea that muscle stretching does not increase the extensibility of the muscles nearly as much as it increases the subject’s tolerance to stretch, and if 4 weeks of 20-minute stretches isn’t going to increase it, I don’t know what will. While this is interesting, the authors contend that clinically, it’s probably not as important to know the mechanism of motion improvement as it is to know how stretching should be performed, and what results can be expected. To that end, one of the most important findings of this study is that the motion gains they found (8 degrees) matched nearly perfectly those of other studies, some of which used much less time- and effort-intensive stretching routines. Given this information, we should expect something on the order of a 5-10 degree increase in straight leg raise motion with the regular performance of a 4-week stretching program.