PainSci summary of Andersen 2010?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 at the bottom of the page, as often as possible. ★★★★☆4-star ratings are for bigger/better studies and reviews published in more prestigious journals, with only quibbles. Ratings are a highly subjective opinion, and subject to revision at any time. If you think this paper has been incorrectly rated, please let me know.
Are muscles “tight” or hard where they hurt? In this experiment, the hardness of the trapezius muscle was tested and compared with sensitive points, before and after intense exercise.
In a dozen healthy patients, the two “typical locations for tender points” were not just soft, but the softest spots in the muscle — the opposite of the what most people (professionals included) would expect. In a dozen healthy patients, the opposite of what most people would expect, and the opposite of what we “know” from trigger point lore. In general, exercise “did not change muscle sensitivity or muscle hardness” and “a heterogeneous distribution of pressure pain sensitivity and muscle hardness was found.” Translation: the conventional wisdom that you’ll find the most pain at “tight” spots in muscles is probably a misleading oversimplification, at best.
It’s not a large experiment, but it didn’t particularly need to be to make this point. Even a small test should have clearly showed that the sorest spots are the hardest — if they really are.
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.
Fatiguing exercise can affect muscle pain sensitivity and muscle hardness, as seen with work-related neck and shoulder pain. Objective methods to assess muscle pain sensitivity are important because the reliability of manual assessment is generally poor.
The aim of this study was (1) to compare coexistence of tender points identified by manual palpation and pressure algometry or hardness assessments and (2) to examine the influence of exercise on muscle pain sensitivity and hardness. Fourteen sites in the upper trapezius muscle were selected for assessments in 12 healthy subjects.
Pressure pain thresholds and muscle hardness were examined by computer-controlled pressure algometry at baseline, immediately after static or dynamic exercise, and 20 minutes after static or dynamic exercise. Before recording of pressure pain thresholds, the trapezius muscle was examined for tender points by manual palpation.
Two sites with low pressure pain thresholds were typical locations for tender points, and these were the least hard sites. However, manually detected tender points were often (29%) not colocalized with most sensitive sites according to the pressure algometry. A heterogeneous distribution of pressure pain sensitivity and muscle hardness was found in the upper trapezius. The short duration of exercise until exhaustion did not change muscle sensitivity or muscle hardness in asymptomatic muscles.
PERSPECTIVE: This study confirms clinical findings with heterogeniosity in pain sensitivity and hardness across the upper trapezius muscle. Developments of new techniques that objectively identify tender points are important, but thus far, manual palpation is best clinical practice.
These three articles on PainScience.com cite Andersen 2010 as a source:
- PS Trigger Points & Myofascial Pain Syndrome — A guide to the unfinished science of muscle pain, with reviews of every theory and self-treatment and therapy option
- PS You’re Really Tight — The three most common words in massage therapy are pointless
- PS Trigger Point Doubts — Do muscle knots exist? Exploring controversies about the existence and nature of so-called “trigger points” and myofascial pain syndrome
This page is part of the PainScience BIBLIOGRAPHY, which contains plain language summaries of thousands of scientific papers & others sources. It’s like a highly specialized blog. A few highlights:
- A Bayesian model-averaged meta-analysis of the power pose effect with informed and default priors: the case of felt power. Gronau 2017 Comprehensive Results in Social Psychology.
- The neck and headaches. Bogduk 2014 Neurol Clin.
- Agreement of self-reported items and clinically assessed nerve root involvement (or sciatica) in a primary care setting. Konstantinou 2012 Eur Spine J.
- Effect of NSAIDs on Recovery From Acute Skeletal Muscle Injury: A Systematic Review and Meta-analysis. Morelli 2017 Am J Sports Med.
- Association of Spinal Manipulative Therapy With Clinical Benefit and Harm for Acute Low Back Pain: Systematic Review and Meta-analysis. Paige 2017 JAMA.