Antagonist muscle activity during stretching: a paradox re-assessed
Two pages on PainSci cite Etnyre 1988: 1. Quite a Stretch 2. Reciprocal inhibition invalidated (15 years ago)
PainSci commentary on Etnyre 1988: ?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 experiment was an early test of the hypothesis of reciprocal inhibition, a key premise of proprioceptive neuromuscular facilitation. They seemed to confirm the phenomenon using wire EMG (electrodes embedded in the muscle), as opposed to skin electrodes, concluding/speculating that the negative results of other tests (like Osternig and Condon) were probably caused by the imprecise superficial electrodes. However, this conclusion was probably definitively contradicted probably definitively by a better experiment conducted by Mitchell in 2009.
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 investigation was to examine and compare the simultaneous electromyographic activity from surface and implanted wire electrodes of an antagonist pair of muscles during a reversal stretching technique. Previous studies reported increased electromyographic activity of a muscle being stretched during antagonist muscle activation. Five male subjects performed a stretching method which consisted of active plantarflexion, followed by active dorsiflexion. Adjacent surface and implanted wire electrodes were applied to the soleus and tibialis anterior muscles. Comparison of the surface electrode recordings showed apparent cocontraction during dorsiflexion. However, no activity was observed on the soleus wire electrode trace during the dorsiflexion phase of the stretching method. Power spectral analysis showed a significant (P less than 0.001) frequency shift between plantarflexion (91.9 V2.Hz-1) and dorsiflexion (66.1 V2.Hz-1) from the surface electrode recordings. Cross-correlation between tibialis anterior and surface soleus activity during dorsiflexion provided strong evidence that the apparent electromyographic soleus signal originated in the tibialis anterior muscle with an average of 8.7 ms delay of the surface soleus signal. Although not generalizable to other studies, it was concluded that in this study the tracings from the surface electrodes, which gave the appearance of co-contraction between antagonist muscles, were actually cross-talk between the electrodes. The rationale for antagonist contraction during stretching in order to inhibit contraction of the muscle being stretched is supported with this evidence and is consistent with those studies which show greater range of motion gains using the reversal technique.
related content
- “Soleus muscle electromyographic activity and ankle dorsiflexion range of motion during four stretching procedures,” Condon et al, Physical Therapy, 1987.
- “Muscle activation during proprioceptive neuromuscular facilitation (PNF) stretching techniques,” Osternig et al, Am J Phys Med, 1987.
- “Neurophysiological reflex mechanisms' lack of contribution to the success of PNF stretches,” Mitchell et al, Journal of Sport Rehabilitation, 2009.
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:
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- Recovery trajectories in common musculoskeletal complaints by diagnosis contra prognostic phenotypes. Aasdahl 2021 BMC Musculoskelet Disord.
- Cannabidiol (CBD) products for pain: ineffective, expensive, and with potential harms. Moore 2023 J Pain.
- Moderators of the effect of therapeutic exercise for knee and hip osteoarthritis: a systematic review and individual participant data meta-analysis. Holden 2023 The Lancet Rheumatology.
- Inciting events associated with lumbar disc herniation. Suri 2010 Spine J.