I ran across a study in The Journal of Strength and Conditioning Research (vol.26.1.Jan.2012) on the Kettlebell Swing and lower back pain, by McGill and Marshall. (There were some other exercises in that study too.) For those who aren’t aware of it, Dr. Stuart McGill is one of the world’s leading spine biomechanicists. So when he publishes something, I look at it.
One of the things he found is that unlike traditional barbell lifting, with kettlebell swings, the loads on the spines are “inverted.”
Because of the arc-like trajectory of the Swing, there is relatively high posterior shear forces* in relation to compressive forces.
*In “regular speak” shearing force is a force that can tear. Compressive force is just that – compressing material together until it explodes/ruptures.
In traditional barbell lifting, there are higher compressive forces compared to tearing forces.
So what does that mean?
It means, according to the researchers that you should have sufficient spinal stability – and sufficiently more spinal stability to swing a kettlebell than lift a bar.
So what’s that mean for YOU?
1. Compressive forces are traditionally associated with back injuries – herniated discs. Kettlebell Swings have low compression forces, therefore, when done correctly, they won’t hurt your lower back. They’re more “forgiving” than barbell lifting.
2. Shearing forces can still cause back injury, so if you’re swinging your KB and have back pain, stop swinging! Your pain most likely means that you either have insufficient spine stability and/or your technique is incorrect.
3. If you even suspect you fall into category #2, you need to add in some spinal stability exercises and polish your technique.
Speaking of polishing technique, I thought it’d be helpful to revisit the “hip hinge” which is the basis of the kettlebell Swing. Especially since it’s early in the new year and we want to make this year better than last. Plus, continually working the basics or fundamentals is always a good thing because helps correct any errors in the “advanced” exercises.
Here’s a video from the Kettlebell Burn stash that presents a 4-Step Formula for “perfect” Swings. I’ve found that these simple cues really have made a big difference in my Swings and my clients Swings. Plus the feedback I’ve gotten from Burn customers has been great.
And most importantly, it’ll help clean up your Swing technique, which, if you don’t have a spinal stability issue, will alleviate and back pain or discomfort while swinging.
So here’s the video. (Give it a couple of seconds to load…)
Let me know what you think.
Now obviously technique is really important to prevent injuries. And most injuries can be prevented simply by using good technique. The problem is, there’s a lot of “opinion” about what good technique is.
After teaching at RKC’s since 2006, I think I’m pretty qualified to offer an opinion on what “good” technique is, including shortcuts to getting good technique. 😉
Don’t forget to leave your thoughts and comments about the Swing video below.