Reciprocal inhibition invalidated (15 years ago)

Jenni Rawlings is a science-based yoga teacher you should follow if you want to be a smartypants in your yoga pants, because she’s always dropping knowledge bombs like this:

Were you taught that if you contract your quads in a forward fold, this will relax your hamstrings because of “reciprocal inhibition”?

Word to the wise, science-based yogis: this idea has been outdated by research for over 15 years! 🤯

When we contract a muscle in a stretch, the opposing muscle doesn’t relax.

Actually inhibiting the opposing muscle (antagonist) would get kind of sloppy, like a tug-of-war team that falls when the other team just lets go. The reality is more like an agreement by one team to lose — but not too badly. Contraction is a balancing act, where one muscle contracts less but still maintains tension.

Which is doubtless vital for evolutionary fitness!

If your quads are shortening, does your nervous system order your hamstrings to relax? To “inhibit” them? This popular idea is probably wrong.

Reciprocal inhibition has been one major premise for proprioceptive neuromuscular facilitation (PNF), the main fancy alternative to lowly “static” stretch.

Up to 2009, the literature had been back and forth on reciprocal inhibition, with a few “no” experiments, like Osternig and Condon, and some “yes” tests, especially Etnyre, who claimed (back in 1988, in the Triassic Period) to resolve the conflicting evidence by showing that you can measure reciprocal inhibition if you just use electrodes stuck deep in the muscle, rather than mere surface electrodes. But Mitchell et al. weren’t satisfied, did a more meticulous experiment, and “did not observe reciprocal inhibition using surface or wire [deep] electrodes.” Womp-womp.

The findings of multiple researchers that a muscle’s tone increases during its antagonist’s contraction seems to be validated by this study. Neurophysiological factors such as reciprocal inhibition and autogenic inhibition appear to not be responsible for the higher ROM gains achieved through PNF stretching.

And just nothing since. Argument over? That detail might be settled. But note that it’s no longer even clear that PNF produces “higher ROM gains” by any means, let alone reciprocal inhibition! See Hill or Lempke.

As usual, stretching is bit of a nothing burger.