ACTIVE INSUFFICIENCY - simple explanation

Active insufficiency is the inability of a biarticulate muscle to contract properly because it is not stretched enough.


For example, bend you elbow and your wrist and try to make a fist. You can't. Why?
Because the flexors in your forearm are in a position in which they are shortened and thus they cannot move the joint in question (make the fist).
This of course is valid only for muscles that move more than 1 joint.


The practical effect for bodybuilding is that some exercises are not really effective when the muscle in question is not stretched sufficiently.





I'll write 3 examples:




- your hamstring is not stretched when you squat (because the bend at the hip is "counterbalanced" by the bend at the knee) thus squat is not the best exercise to hit the hamstring. Good exercises specifically for the hamstring are e.g. good morning or stiffed legs deadlift, in which the hamstring works in a stretched position.




- biceps. Biceps works on 3 joints. Consider that the short head of the biceps (the internal one) works even to flex (raise) the shoulder. Its contribution is minimal, but the point is that this short head cannot be worked effectively if you flex your elbow (curl) when your shoulder is raised.

This means that exercises like preacher curls, concentration curls, cheat curl (raising the elbow before flexing it) and even chin ups are not really effective [I]on the short head[/I] of the biceps.

For this kind of curl much of the load is moved to the brachialis, and away from the biceps.




- triceps. The long head of the triceps (that acts on 2 joints) can be worked effectively only when it is stretched. That's why you need to do skullcrushers/extensions etc. and on the other hand, benching does not work (enough) the long head.







Feel free to comment.

So you are supporting...

1) the common belief that stretching is beneficial?
2) that certain movements should be performed because they increase emphasis on certain muscle heads?

...

Quote
your hamstring is not stretched when you squat (because the bend at the hip is "counterbalanced" by the bend at the knee) thus squat is not the best exercise to hit the hamstring. Good exercises specifically for the hamstring are e.g. good morning or stiffed legs deadlift, in which the hamstring works in a stretched position.

Recipricol inhabition. Hams don't work through most of the squat because they are neurally turned off. Not because they are not stretched.

Not sure what point you're making with the post, other than just bringing the info to the surface and talking about it.

Either way, I agree with it, also made me think why the PLer style squat is better for hams then the Oly style.
My guess is with the hips pushing backwards and the wider stance, the hamstrings are stretched more during the movement than with oly style.

[QUOTE=DJAuto;766529743]So you are supporting...

1) the common belief that stretching is beneficial?
2) that certain movements should be performed because they increase emphasis on certain muscle heads?

...[/QUOTE]

1) no, this has nothing to do with the activity of stretching.

2) yes, that certain muscle [heads] receive much more emphasis in certain movements: they need a certain position to be activated more effectively.
This should be taken in consideration when choosing an exercise, e.g. if you want to hit your biceps then preacher curls is not the best choice.



[QUOTE=rutzilla;766543173]
Recipricol inhabition. Hams don't work through most of the squat because they are neurally turned off. Not because they are not stretched.[/QUOTE]

I get what you're saying; but the hamstring in the squat works only to extend the upper leg, thus it is not the antagonist of the quad in this case.
Even if there's a head of the quad that raises the leg, I would think there's no reciprocal inhibition quad-hamstring because they don't work around the same joint at the same time.

Feel free to tell me if I'm wrong.




[QUOTE=chazzy1864;766544693]Not sure what point you're making with the post, other than just bringing the info to the surface and talking about it.

Either way, I agree with it, also made me think why the PLer style squat is better for hams then the Oly style.
My guess is with the hips pushing backwards and the wider stance, the hamstrings are stretched more during the movement than with oly style.[/QUOTE]

No point, I just realized this and I wanted to hear what experienced lifters think.

And yes, with the powerlifting squat you bend your hip joint much more and this stretches the hamstring more than in the Olympic squat.

I know what your saying about a stretched muscle and contraction, if there is slack the contraction target muscle won't get motor units fired. At least thats what I think your saying.

Training a muscle in a contraction position is worth adding into training, for the variation.

[QUOTE=chazzy1864;766544693]Not sure what point you're making with the post, other than just bringing the info to the surface and talking about it.
[/QUOTE]

Exactly my thoughts.

Integral stuff...but not exactly novel.

[QUOTE=noflyingcars;766505703]bend you elbow and your wrist and try to make a fist. You can't. Why? Because the flexors in your forearm are in a position in which they are shortened and thus they cannot move the joint in question (make the fist).[/QUOTE]Why did you say elbow? The finger flexors cross the wrist joint, it is bending the wrist that makes forming a first more difficult, not the elbow.

[QUOTE=rutzilla;766543173]Quote
your hamstring is not stretched when you squat (because the bend at the hip is "counterbalanced" by the bend at the knee) thus squat is not the best exercise to hit the hamstring. Good exercises specifically for the hamstring are e.g. good morning or stiffed legs deadlift, in which the hamstring works in a stretched position.

Recipricol inhabition. Hams don't work through most of the squat because they are neurally turned off. Not because they are not stretched.[/QUOTE]


Though the hamstrings are not fully activated, doesn't mean they aren't activated at all (Recipricol Inhibition). The hamstrings are actually contracting isometrically developing enough force to keep you in the squat position. without the hamstrings, you would simply fall over. They are activated throughout the whole squat cycle.
(source -I'm an Exercise Scientist)