Open question regarding use of CORE muscles

[Jorge Colon]

Dear Coaches and Enthusiasts,

I need help understanding how the intense isometric contraction of the muscles generally known as the CORE (abs/gluts) enhances the ability to carry weight and exert force through the upper body structure (arms, shoulders) with relative ease and an almost relaxed feeling. I understand proprioception but the term merely describes the process but not HOW exactly the process works. For example, can it be explained with biomechanics or must we use other disciplines (sciences) in addition?

Thank you in advance for your help.

[rbibbs]

"Researched lay perspective", Jorge... any force generated by your arms or legs has to be supported/counterbalanced by a core force. (I also think of "core" as including transitional structures-- the shoulder girdle and pelvic girdle.) A corollary to this, would be that no matter how strong our arms are, they can only exert as much force as our core, including transitional structures, can counterbalance.

In my own experience, trying to develop peripheral strength (arms) without developing the core strength and articulation to support it, was damaging. My elbows complained loudly, when I could hear them over my shoulder tendons, that is. But enough about me.

Proprioception enters the picture, when we're training our motor-neurology to exactly counterbalance core vs peripheral exertion, for the maximum effective generation of force in a given vector. It's an edge in performance sports, and in everyday life. Like getting "free energy" just by coordinating it efficiently.

[Jorge Colon]

Bibbs,

Thank you. Using what I understood from your explanation, then if I soften my CORE or use it ineffeciently, what is counterbalancing my arms? My understanding is that it would be my shoulder girdle and then in turn my feet, no? I know I am skipping some steps here but I have put it this way for the sake of brevity.

My purpose is to better understand this phenomena in light of how resistance strength training differs from this concept of being grounded as in Tai Chi or other similar CHI based strength practices. Which brings me to my next point. Is this "free energy" the same as CHI in Asian paradigms and is the explotation of this energy available in an incrementally increasing manner as we become more effeciently coordinated?

Let me use a practical example. In using resistance bands to rotate torso (not waist) then the hips with torso, then with turning in the leg and finally stepping out while rotating all three, if I allow my chest to sink in slightly the pressure feels as if it is transferred to my feet and CORE while my arms and upper structure hardly makes any effort. However, if I pull my shoulders back and engage my upper torso and shoulders, I must make a real effort in that upper structure, including arms, while rotating.

Any help from any one is welcome. Thanks again Bibbs.

[Coach Billew]

Jorge,

I don't have much to offer here but just a quick thought in response to your last post.

You wrote:
"if I allow my chest to sink in slightly the pressure feels as if it is transferred to my feet and CORE while my arms and upper structure hardly makes any effort. However, if I pull my shoulders back and engage my upper torso and shoulders, I must make a real effort in that upper structure, including arms, while rotating."

You might also want to think about how that change in structure effects your breathing. It seems like in the first example you are compressed and therefore largely working in the control pause, and locking down the body whereas in the second example you probably have air in your lungs and therefore do not have the same sense of internal stillness and rootedness. I don't know if this makes a significant difference in terms of your question, but it seems worth considering.

[rbibbs]

I don't have the comprehensive, definitive answer Jorge. I'm also not conversant in chi, so I can't contrast that.

In your example of arm force... how does the counterforce reach your feet? It has to go through the core. We can think in terms of counterforce returning to the ground, or of force originating at the ground, but if you've ever watched astronaut videos from the space shuttle, you see that it's quite difficult to exert any force without a fixed point of reference to originate the force/support the counterforce (either way you choose to look at it). If the core is 'softened', it's going to elastically absorb the counterforce, making your arms have to work a lot harder to deliver the same intensity.

One can thoroughly exhaust one's self at the boxing gym, trying to strike effectively using only arm/shoulder force. It's just logical that the most power is going to be generated by the largest muscle mass. In striking, I tend to think of core power generating the force, and arm strength connecting/articulating it. Hope that helps.

[bob_stra]

Jorge

There are a variety of reasons for this phenomenon. Proprioception is not one of them - infact, proprioceptive ability probably *decreases* as tension increases. Think of closing your eyes while holding a feather. A fly lands on the feather - will you notice? Probably. Now imagine the same situation, except you're holding a 20kg dumbbell. Too much "background noise" for you to feel the fly.

Some possible explanations for your observations then, from most likely to least likely -

Firstly, isometric contraction allows for the *efficient transfer* of force, generated via the powerhouse (legs / pelvis) through the spine.

For example -

Imagine you were going to throw a punch. Without the correct tension / allignment in your arm, force would be lost at the shoulder, elbow and wrist. Similarly, without the correct pattern of contraction in the abs, the force couldn't arrive from the legs into the arm in the first place.

IOW --> too loose = loss of force at joint = less "work" possible

Secondly, I imagine you know abt hyperirradiation. Contracting A forces B to partially contract. So that 100% A + 50% B is greater than 100% of A alone.

The downside however is that for a muscle to fully contract, it needs to relax first. So quite possibly this method of hyper-irradiation is inefficient when you want 60-100% force contraction from B alone. (yes, I can think of some circumstances - how about walking?). Furthermore, according to some authors, the feeling of co-ordination is directly proportional to equal levels of work being done by all active muscles. So that big muscles must contract (proportionally) the same as little ones.

Thirdly, you might consider somato-visceral reflexes. There is plenty of evidence that it works in the other direction - stimulation of the nerves from the T4 level (via massage, adjustment, movement) causes an increase in heart rate, beat or both (in some persons). Nothing to say that this can't go the other way AFAIK. So that increasing the heart rate (via breath holding) might cause a reflexive increase in the max. contraction of the muscles that innervate from T4 (trapezius etc).

Fourthly - increased intra-abdominal pressure significantly increases trunk muscle activity anyways. Thus better transfer of force as per (1).

http://tinyurl.com/3yebh

Final comment - what works best for force *production* may not be best for force *absorbtion* nor force *co-ordination.* But that's another post ;-)

[Jorge Colon]

Rick, Slade and Bob,

Thank you for your feedback. All of it helps as I continue exploring everyday.

Best regards,