Deactivating Muscles

[desmond]

I floated the idea in the "crap I hurt my back website" but have now found an article broadly consistent with the idea and wanted to make a thread about it.

Suppose you want to target yours lats on close grip underhand chin uping?

To deactivate the biscep, could you stretch it intensely before the exercise which will reduce the bisceps strength and therefore ability to contribue to the exercise (see tactic 6 in this article Figure Athlete FORUMS - My TMAGNUM

If you were to work say hamstrings/quads on different day, this concept could seemingly be used, or say for shoulders and chest for people who have difficulties isolating the chest.

Anyone tried this?

 

[Jocques Straap]

You link didn't work

I would think you would have much better results by pre fatiguing your biceps with some curls, before getting to your chin ups. In my experience, intense stretching reduces muscle strength my a very, very small amount, if anything at all.

 

[desmond]

T-Nation.com | Tricks of the Trade — Get Strong Fast!

I think I gave wrong link by mistake. Apologies

COPYING below relevant part:

Tactic #6: Antagonist Stretching

I can't trace antagonist stretching to one specific coach, but it's been used for a long time and clearly works!

It's well documented that intense stretching prior to a muscle contraction greatly reduces the force production potential for that contraction. That's one of the reasons why it's best to stretch after a workout rather than before it.

We can use this little tidbit of information to our advantage. There's this thing called "antagonist co-contraction" which can actually reduce our capacity to lift big. If an antagonist muscle (a muscle opposite the function of the target muscle) has a lot of tension in it, it'll take more force for the agonist muscle to produce a certain movement.

Basically, if your triceps are contracting, it'll be harder to curl anything impressive. The triceps are elbow extensors, while the biceps are elbow flexors; the contraction of an extensor will make the flexion harder to do.
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So, if we can reduce the contraction potential of the antagonist muscles, their level of co-contraction will be less. As a result, the inhibitory effect of the antagonist will be reduced, thus allowing you to lift more. If the antagonists are contracting, not only do you have to fight the barbell, you have to fight the antagonist muscles, too!

In the bench press, the prime movers and synergists (agonists) are the anterior deltoids, the triceps, and the pectorals/serratus. So, we can conclude that the antagonists are the posterior deltoids, the biceps, and the latissimus dorsi/rhomboids. Now, we know that stretching a muscle will reduce its capacity to contract, so stretching the antagonists right before attempting a bench press will facilitate the action of the prime movers and synergists!

 

[Jocques Straap]

Stretching antagonists, and stretching secondary/primary muscles isn't the same thing. You mention the biceps and the lats, for the chin up. This is much different than pec/back mentioned in the article.

antagonist co-contraction, is necessary for joint stability. When any muscle group contracts, the opposite muscle group must also contract, this action stabilizes the joint. An easy example is the knee, this joint has a slide/roll motion. Flexing the knee results in an contraction of the hamstrings, and the rectus femoris. As the hamstring contracts, it pulls on the tibia resulting in a rolling action of the tibia against the femur. The Rectus femoris contracts pulling on the patella, which acts on the tibia, resulting in a sliding action of the tibia. This keeps the joint safe, and in it's best possible position for force production.

We also have reciprocal inhibition to consider. this is when a muscle group is sent a transmission to relax when the antagonist muscle is contracting. Again here, this is a safety mechanism and also aids in maximal force production.

Lets take this a step further. Why not fatigue the antagonist muscle group by doing a specific exercise for the antagonist muscle. After some rows, try maxing out on bench. You will notice that since your antagonist muscle are fatigued, you will not be able to bench as much.

The hamstrings show significant activation during a squat, even though it seems like this would counteract the action of the quads. Which it does, but is necessary in order to hold the knee in a stable position. If you were to limit the activation of the hamstring, the knee would be pulled into a compromising position(tibia would be pulled forward, resulting on stress on the ligaments). Then a signal would be sent to the quad, limiting activation of the quad to keep the knee in a safe position.

Thibs makes it seem like their is a regular misfired motor unit in the antagonist muscle group which hinders your power, which isn't the case. Misfires can occur, and usually result in an injury to the weaker muscle of the pair. Any activation of an antagonist muscle group although does act against the primary mover, it does this to aid in force production and safety of the joint.

Why don't you give it a try Desmonds? It's not something that's going to make a significant different either way and won't end up hurting you, so if you like it great!