Showing posts with label muscle performance. Show all posts
Showing posts with label muscle performance. Show all posts
Wednesday, August 19, 2009
Arthrokinetic Reflex: Joint action affects Muscle Performance
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This post is about the arthrokinetic reflex. The term goes back to 1956 and suggests that something done to a joint can reflexively cause muscle activation or inhibition. Eric Cobb in Z-Health (overview) makes use of this concept to show how something as simple as head position can have a negative impact on muscle activation, and that conversely, joint mobilization (and better head position) can have an immediate benefit for freeing up muscle activation for improved strength performance.
There's some interesting ideas around how these reflexes relate to threat and threat modulation, but we'll come back to those at another point. Right now, let's see the effect in action.
Just to walk through the following video because the audio seems to be a bit low, here's what's happening.
First: demonstration of a classic issue in the Kettlebell Swing: head is way back when going for the hip snap. Why might this be a problem? that head position, that far back on the neck, may actually be reducing available power and consequently compromising the work a person wants to do.
How can we demonstrate this claim?
Second: Rikki Prince kindly volunteers for a hamstring muscle test, head in neutral position.
All that's happening in the muscle test is that i am meeting the force that Rikki is producing so that there's equilibrium.
Third: Rikki cranks his head back for the second hamstring test
In this case, i'm using the same force on Rikki's leg as previously used to balance his leg pushing up, and his leg goes down - right down - to the ground.
Now, one could say ha you're cheating, you're using way more force. First, in the video - does it look like i'm pushing hard? face it, i'm not a big person, and Rikki's considerably taller and larger and more muscular than i. Second, this test could be done with a machine where forces are calibrated - so if you have the apparatus by all means do so. Third, you'll have to believe me, yes, that Rikki wasn't faking it - this you can also test with yourself and a colleague if you learn the technique to match people's strength. I've done this with a room full of people and there's always one person who says "didn't work for me" - I'll take that one stat of 1 out of 25. But it usually turns out when retested by someone else, it's there.
I also was asked to demo this at the May 09 RKC Denmark cert. Kenneth Jay volunteered (shown left using mark cheatham as "the wall") - for those who have met him, do you think KJ would fake this test?
Fourth: Head back in neutral, re- test. In this case we see the leg is a lot stronger than just a moment before, and that's just from getting out of the head cranked position.
Fifth: Going further to clean up the muscle test, and re-test. Without giving poor Rikki a break we do two Z-health neck mobility drills - just to open up those neck joints more deliberately. We retest. The bigger wobble is now out of the leg, and we're as stable as we were when we started.
If i was working with Rikki further, i'd keep going to do a movement assessment to get at that little bit of rumble that was there at the start and is still present at the end.
Sixth: applying this reflex notion to the swing
At the end, a quick demo of a few swings with the head in neutral, using the eyes to look up, rather than the head cranking back. You can't see it, but i'd encourage you to try it: this technique of keeping the head neutral combined WITH the eyes charting the movement actually provides a double shot benefit for the swing. It FEELS much smoother and stronger and more effortless.
This double shot is discussed further with liberal illustrations and Eric Cobb quotations and b2d synthesis/analysis in terms of "efficient movement" in yet another application: the kettlebell front squat.
If you'd like more detail on the eye position in the swing, see Cobb's article cited above, and look for "eye position kettlebell swing experiment."
Take Away: the Arthrokinetic Reflex - works both ways
What we do with a joint has a reflexive effect on muscular activation/inhibition. ANY joint; All Muscles - pretty much.
So what this demo shows us three things + a heuristic
Related Posts
Thanks for reading. Tweet Follow @begin2dig
There's some interesting ideas around how these reflexes relate to threat and threat modulation, but we'll come back to those at another point. Right now, let's see the effect in action.
Just to walk through the following video because the audio seems to be a bit low, here's what's happening.
First: demonstration of a classic issue in the Kettlebell Swing: head is way back when going for the hip snap. Why might this be a problem? that head position, that far back on the neck, may actually be reducing available power and consequently compromising the work a person wants to do.
How can we demonstrate this claim?
Second: Rikki Prince kindly volunteers for a hamstring muscle test, head in neutral position.
All that's happening in the muscle test is that i am meeting the force that Rikki is producing so that there's equilibrium.
Third: Rikki cranks his head back for the second hamstring test
In this case, i'm using the same force on Rikki's leg as previously used to balance his leg pushing up, and his leg goes down - right down - to the ground.
Now, one could say ha you're cheating, you're using way more force. First, in the video - does it look like i'm pushing hard? face it, i'm not a big person, and Rikki's considerably taller and larger and more muscular than i. Second, this test could be done with a machine where forces are calibrated - so if you have the apparatus by all means do so. Third, you'll have to believe me, yes, that Rikki wasn't faking it - this you can also test with yourself and a colleague if you learn the technique to match people's strength. I've done this with a room full of people and there's always one person who says "didn't work for me" - I'll take that one stat of 1 out of 25. But it usually turns out when retested by someone else, it's there.I also was asked to demo this at the May 09 RKC Denmark cert. Kenneth Jay volunteered (shown left using mark cheatham as "the wall") - for those who have met him, do you think KJ would fake this test?
Fourth: Head back in neutral, re- test. In this case we see the leg is a lot stronger than just a moment before, and that's just from getting out of the head cranked position.
Fifth: Going further to clean up the muscle test, and re-test. Without giving poor Rikki a break we do two Z-health neck mobility drills - just to open up those neck joints more deliberately. We retest. The bigger wobble is now out of the leg, and we're as stable as we were when we started.
If i was working with Rikki further, i'd keep going to do a movement assessment to get at that little bit of rumble that was there at the start and is still present at the end.
Sixth: applying this reflex notion to the swing
At the end, a quick demo of a few swings with the head in neutral, using the eyes to look up, rather than the head cranking back. You can't see it, but i'd encourage you to try it: this technique of keeping the head neutral combined WITH the eyes charting the movement actually provides a double shot benefit for the swing. It FEELS much smoother and stronger and more effortless.
This double shot is discussed further with liberal illustrations and Eric Cobb quotations and b2d synthesis/analysis in terms of "efficient movement" in yet another application: the kettlebell front squat.
If you'd like more detail on the eye position in the swing, see Cobb's article cited above, and look for "eye position kettlebell swing experiment."
Take Away: the Arthrokinetic Reflex - works both ways
What we do with a joint has a reflexive effect on muscular activation/inhibition. ANY joint; All Muscles - pretty much.
So what this demo shows us three things + a heuristic
- squishing up a joint, like cranking back the head in a swing or lift, has immediate effect on muscular activation. In the case of squishing, we get inhibition.
- We see that going to a more open joint position (head neutral) has an immediate effect on muscle activation.
- We see also that that effect can be enhanced further with self-moblization around that joint.
- heuristic: maintaining optimal range of motion in a joint enables best strength performance/efficiency.
Related Posts
- If you're interested in more of these mobilization techniques, i'd recommend starting with the z-health r-phase and neural warm up package (described here).
- overview of z-health - neurological approach - article index
- If you'd like to learn about z-health theory and practice and have it more directly applied to kb work, and if you're gonna be in the UK on October 18, please come to the kb essentials and z-heatlh theory and practice workshop.
Thanks for reading. Tweet Follow @begin2dig
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