Squat Research paper

[Fatfacts25]

There is an interesting research paper I happened upon today. It states the wider the stance the more the Gluteus Maximus is activated. There’s a whole bunch of stuff in it. Thought some people might like to discuss some of it.....
The link:
Muscle Activation in the Loaded Free Barbell Squat: A Brief... : The Journal of Strength & Conditioning Research

[Mark Rippetoe]

Sure.

[Mark Le Comte]

“Research has also shown that muscle activation of the prime movers in the squat exercise increases with an increase in the external load.”

Good God!

[Fatfacts25]

It tests results at various depths. I want to say it states that the butt muscle is mainly affected by depth. There’s a lot there for me to remember all of it. Some less interesting stuff about squat vs. leg press and smith machine squat is in it. The stuff about what muscles are activated more in various stance widths is more fun to me.

[Mark Rippetoe]

Find the paper that demonstrates that surface EMG is a proxy for motor unit recruitment.

[Jonathon Sullivan]

Find the paper that demonstrates that surface EMG is a proxy for motor unit recruitment.

Of course it's a proxy. It's used as a proxy all the time.

The challenge put should be: Find the paper that demonstrates that surface EMG is a good proxy for motor unit recruitment.

[Mark Rippetoe]

An excellent point. A valid proxy.

[jfsully]

This is sort of interesting, and like everything in physiology is way more complicated than it has a right to be. It turns out that EMG is a good proxy for MU recruitment in some cases but not in others. Here are a couple a papers that argue both sides:

Point:Counterpoint: Spectral properties of the surface EMG can characterize/do not provide information about motor unit recruitment strategies and muscle fiber type/japplphysiol.90598.2008

And this is from the part that argues FOR emg as a good proxy:

However, one should not expect to see substantial changes in power spectra when studying single-task experiments such as an isometric ramped increase in force (4), selective recruitment of fast-twitch muscle fibers during lengthening contractions (2), and/or EMG activity during an explosive contraction (8). In such experiments, the power spectrum is determined by the single task studied and substantial changes in the power spectra should not be expected.

I'm not really steeped in this literature, and I always found the neuromuscular junction to be the least interesting area of neurology so I confess to neglecting it in my studies, but I think that this disclaimer would cover barbell lifts fairly well.

This is surprising, as EMG should be able to tell us about motor unit recruitment and fiber types, and there sure seem to be a lot of studies that use it that way. This is kind of like an astronomer spending years getting detailed images of elaborate galaxies only to find out that they are smudges on the lens of his telescope. Bummer. Guess we have more to learn, even about the simple uninteresting stuff!