Changes the load when using different grips in the bend of the forearm. Myths and reality?
Author: Andrey Antonov
In the February issue of the magazine, my article «Bending of the forearm with a standing bar» was published in which I made a biomechanical and anatomical analysis of this exercise. I analyzed only the classic version of the exercise with supined tar and explained why when using grips of different width we will load both heads of biceps absolutely equally. But after the publication, I got a lot of questions about how the burden changes when using different rotary grips. That is, which muscles work more when using supined, hammer and penetrated grips. The subject is rather interesting. In my favorite textbook of anatomy under the authorship of M. F. Ivanitsky unfortunately gave an analysis of muscles involved in flexing of the forearm from the main strut, implying supining position of the forearm, that is, palm forward. But knowing the places of origin and places of attachment of muscles involved in movement it is not so difficult to make such analysis. The textbooks indicate the following muscles:
1. Humeral muscle
3. Shoulder-beam muscle
4. Round pronator
The performance of this movement is also assisted by those muscles that begin from the inner supersaturus of the humerus and continue on the forearm and brush. We will talk about these muscles and their participation in the movement a little later. For starters we will analyze the work of shoulder muscles, i.e. biceps and shoulder muscle. Many like to call her Latin brachialis (m. Brachialis), but in my opinion this name has not taken hold as much in us as the name «biceps.» Here the biceps «double-headed muscle of the shoulder» is called only specialists, so Latin term, (more precisely its part, the full name «biceps brachia» (m. Biceps brahii)) has become more familiar since childhood. But, naturally, both variants of names are permissible. To whom as it is more convenient.
With the shoulder muscle, everything is simple. The muscle begins from the anterior surface of the humerus, and is attached to the buginess of the ulnar bone and its coronary process. As I have written many times, the elbow joint is block-like. It has only one axis of rotation and no rotation. And at penetrated grip and at hammer and at supined position of elbow bone in relation to shoulder does not change. And when performing the flexion of the forearm, the shoulder muscle works the same way with any tailing. It may be underfilled when performing the exercise with backfill, as in this variant the limiting link is the forearm muscles and they fail earlier than the shoulder m and biceps, but we will talk about this in more detail later.
What happens to biceps when the tar changes. Two of its heads begin on a blade, long from an over-the-top bugger, and short from a beak-shaped process, and it is attached to the bugginess of the radial bone and the fascia of the forearm. Let us not affect the function of shoulder bending here, but stop exclusively on forearm bending and forearm supination. How does biceps work when the shoulder is fixed? First of all, prearm supination is carried out. It ‘s obvious from the structure of the hand. In order to bend the forearm of the free arm, it is necessary to apply a force, since the length of the lever from the point of attachment of the biceps to the center of the forearm mass is sufficiently large. And the length of the lever when performing forearm supination is insignificant and therefore the supination requires significantly less effort. That is, first biceps produces forearm supination to rest. The stop may be anatomical, i.e. limited joint configuration. It can be mechanical, i.e. limited by the rigid shape of the handle used or muscle when the muscles of the forearm pronators are stressed. In either case, when forearm supination becomes impossible, biceps begins to bend the forearm. When the forearm is bent by the penetrated tail, complete biceps contraction does not occur in the distal part because part of the tendon is wound on the radial bone. But in the starting position biceps for the same reason are more stretched. Therefore, the mechanical work he does when he folds his forearm will be identical when using any tar. Therefore, it is generally believed that when the forearm is bent with the suppressed tar, the biceps is loaded more, and when the hammer or penetrated tap is bent, the shoulder muscle is not justified. Both shoulder muscles are loaded equally when using any tar.
What can ‘t be said about forearm muscles. Directly in the flexion of the forearm involved all muscles that start from the humerus. Let me list them all:
1. Round pronator
2. Beam sgibatel of a wrist
3. Elbow sgibatel of a wrist
4. Superficial sgibatel of fingers
5. Shoulder-beam muscle
6. Long radial wrist extender
7. Short radial wrist unbend
8. Elbow razgibatel of a wrist
9. Razgibatel of fingers
10. Muscle instep support
According to the laws of anatomy, muscles flexing in the elbow joint must cross the horizontal axis of the elbow joint and be in front of it. And here we see that in case of different rotational position of forearm different of the above muscles will meet the specified criteria. That is, when the forearm is flexed with the suppressed tar, the main load will fall on the muscles of the flexors and pronator. When bent with hammer tail on shoulder-beam and adjacent to it both flexors and extenders. And when bending penetrated, extenders and supinator will be activated more actively.
Also when performing flexing of forearm with different grips, load on muscles performing movements of hand and fingers changes.
When performing the exercise with the supined tar in static mode, six muscles perform bending of the hand and bending of fingers. These are strong enough muscles, they easily cope with the task and the limiting link in the exercise do not become. In addition, the load on the finger flexors is low. The projectile presses on the fingers in the area of the proximal phalanx, where the power potential is greatest.
In the course of the exercise, six muscles, which carry out the retraction of the brush, can become a limiting link with a hammer tail. These muscles initially have less force potential and require special training. Therefore quite often, but not always, athletes with supined tar can raise more weight than hammer.
But when using permeated tar, the weight of the burden used will always be less. First, the force potential of the forearm muscles involved in the flexion of the forearm, wrist extenders, fingers, and supinator is much lower. Second, seven muscles of hand extenders work in static mode, and they are much weaker than muscles performing bending and retraction of hand. Third, the load on the muscles of the finger flexors is greater here than in the previous embodiments. The projectile presses on medial phalanges of fingers, and in the upper part on distal and to hold it they have to apply a large force. Even with the help of thumb-driving muscles. And, fourthly, in performing this exercise simultaneously work muscles antagonists — muscles flexors of fingers and muscles extenders of hand. They reduce each other ‘s power potential. Still outstanding Soviet physiologist Y. M. Kotz in his textbook «Sports Physiology,» on limitation of unnecessary activity of muscles of antagonists for more complete manifestation of maximum arbitrary force.
As a result, the expediency of performing forearm bending with permeated tar in bodybuilding is highly questionable. Forearm flexors are underperforming, and more effective exercises can be offered for hand extenders and finger flexors. The only athletes who can reasonably use such exercise in the trainings, are armrestlers. In order to perform a breakdown of the grip from an uncomfortable position, when the rival is holding his fingers hard, it is sometimes necessary to apply in force mode a movement very close in structure to the bending of the forearm with penetrated tar.