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No, “stretching“ did not work for nurses with back pain

PainSci » bibliography » Chen et al 2014
updated
Tags: treatment, stretch, back pain, exercise, self-treatment, muscle, pain problems, spine

Two articles on PainSci cite Chen 2014: 1. Quite a Stretch2. Complete Guide to Low Back Pain

PainSci commentary on Chen 2014: ?This page is one of thousands in the PainScience.com bibliography. It is not a general article: it is focused on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided wherever possible.

This is a trial of the effectiveness of stretching for 64 nurses with significant chronic back pain, compared to another 63 with back pain who just did ordinary activity without stretching. The abstract reports positive results, declaring that stretching is “an effective and safe nonpharmacological intervention.” Isn’t it great when Science tells us what we want to hear? Unfortunately, it’s a terrible study, just complete garbage, in several ways.

The abstract reports “statistically significant” results without any reference to effect size, which is a common bit of scientific “sleight of hand” to impress the naive, routinely condemned by experts for decades now; it almost always means that the actual effect was nothing to brag about (or they would have). This is a particularly classic example, and it’s enough to cast significant doubt on the value of the data. The actual differences in pain levels between the groups were trivial — and what little there was is probably not because of the stretching. There were major confounding factors here.

The so-called “stretching” protocol included a wide range of warm-up exercises that went well beyond simple stretching, plus even some core strength training and relaxation! This is kind of like saying that you’ve proved that olives can get you drunk by testing the effect of martinis that happen to have olives in them. There’s no way to know that it was actually the stretching that was beneficial if it was mixed in with a bunch of other things that could plausibly have the same effect.

This study is not designed to actually answer the research question. It’s so poorly set up that I think it’s weird that it passed peer-review.

It’s also poorly written and demonstrates a generally lousy grasp of critical thinking and scholarship. For instance, the discussion section launches with sweeping claims about the biological benefits of stretching, substantiated only by a reference to a sports medicine textbook. Good grief.

~ Paul Ingraham


Common issues and characteristics relevant to this paper: ?Scientific papers have many common characteristics, flaws, and limitations, and many of these are rarely or never acknowledged in the paper itself, or even by other reviewers. I have reviewed thousands of papers, and described many of these issues literally hundreds of times. Eventually I got sick of repeating myself, and so now I just refer to a list common characteristics, especially flaws. Not every single one of them applies perfectly to every paper, but if something is listed here, it is relevant in some way. Note that in the case of reviews, the issue may apply to the science being reviewed, and not the review itself.

  1. Declares statistical significance without acknowledging low effect sizes. Major foul.
  2. Poorly chosen experimental and/or control groups, not possible to actually answer the question
  3. Damned with faint praise — technically positive results (at least partially) that don’t actually impress.
  4. Poorly written enough to cast doubt on the quality of the study.
  5. A junky or trivial little study that was probably published more to pad someone’s resumé than to actually answer a research question. We are drowning in studies like this, which mostly just muddy the waters with more inadequate data.

original abstract Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

The purpose of this study was to examine the effectiveness of a stretching exercise program (SEP) on low back pain (LBP) and exercise self-efficacy among nurses in Taiwan. A total of 127 nurses, who had been experiencing LBP for longer than 6 months and had LBP with pain scores greater than 4 on the Visual Analogue Scale for Pain (VASP), were randomly assigned to an experimental group and a control group. The experimental group (n = 64) followed an SEP, whereas the control group (n = 63) was directed to perform usual activities for 50 minutes per time, three times a week. Data were collected at four time points: at baseline, and 2, 4, and 6 months after the intervention. During the 6-month follow-up, the experimental group had significantly «“significantly”» lower VASP scores than did the control group at the second, fourth, and sixth months. In addition, the experimental group showed significantly «“significantly”» higher exercise self-efficacy than did the control group at the fourth and sixth months. A total of 81% of the participants in the experimental group reported a moderate to high level of LBP relief. The findings can be used to enhance self-care capabilities with SEP for nurses that experience LBP or are vulnerable to such work-related pain. SEP is an effective and safe nonpharmacological intervention for the management of LBP.

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