According to the shape of muscle fiber, human skeletal muscle can be divided into spindle muscle, flat muscle, square muscle, round muscle, sphincter muscle and feather muscle.
The deltoid muscle is feathered, the front and rear bundles are single-feathered, the middle bundle is polypoid, and the deltoid muscle is attached to the shoulder joint. Because the muscle fibers of deltoid muscle are pinnate, deltoid muscle is strong and powerful, but its range of motion is limited, and the humerus can only stretch 70 degrees when contracting.
Because of the characteristics of pinnate muscle, the training of deltoid muscle must change its angle frequently, so that all muscle fibers can be trained effectively.
Before talking about training deltoid muscle, let's first understand the shape and function of lower deltoid muscle.
1, form
Deltoid muscle is also called. Tiger muscle? , is a kind of? Inverted triangle? Muscle, located under the skin of the shoulder, covers the shoulder joint from front to back. We also call these three parts deltoid anterior bundle, posterior bundle and middle bundle.
The deltoid is pinnate, so it is pinnate. The front and rear bundles are single-feathered, and the middle bundle is multi-feathered, which together form a full and prominent shoulder shape.
Starting point: the anterior muscle bundle starts from the lateral half of clavicle, the middle muscle bundle starts from acromion, and the posterior muscle bundle starts from acromion.
End point: deltoid tubercle of humerus.
2. Function
When the whole muscle fiber contracts, the upper arm extends; When it is close to fixation, the shortening of the anterior fiber will lead to the internal rotation and bending of the upper arm shoulder joint; When the central fiber contracts, the upper arm opens; When the posterior fiber contracts, the upper arm extends and rotates outward at the shoulder joint.
After understanding the function and structure of deltoid muscle, let's talk about two better moves to practice deltoid muscle.
1, gantry side lift
This action is done on a gantry stretcher. Usually we usually use dumbbells or barbells to lift horizontally before. The trajectory of rope movement is variable, which can make the toes of deltoid muscle get more exercise.
Action process:
Adjust the frame to the lowest position, with your feet shoulder width apart, lift your shoulders, tighten your core muscles, put your arms at your sides, and hold the handle with one hand.
Exhale, start to contract to the heart, and lift your arms forward until they are on the same plane as your eyes. Then continue to inhale, start centrifugal contraction, slowly lower your arm, return to the starting position, and repeat this action.
When one arm is finished, do it with the other arm. It is recommended to practice 4-6 groups, each group 12- 15 times.
Note: this action has a good training effect on the toe and clavicle of pectoralis major, and also has a certain training effect on the short head of biceps brachii.
2. Lift horizontally with one hand
The most common way to practice this movement is to stand, which can be said to be one of the most popular movements in triceps training. The action we are going to talk about today is also made of dumbbells.
However, we changed the posture to lie on the side, so that the deltoid muscle can exert its maximum strength at the beginning of the exercise, while the standing posture is just the opposite to the side lift, and it can exert its maximum strength at the end of the exercise.
This action provides more motion angles for deltoid muscle and maximizes the training effect.
Lie on your side on the bench, bend your forearm to support your body, hold the dumbbell in the forehand position with your upper arm, then exhale and start to contract towards the center, then raise your arm, continue centrifugal contraction, inhale, slowly lower the dumbbell to the initial position, and then repeat this process.
When one arm is finished, switch to the other arm to finish. It is recommended to practice 4-6 groups, 4-6 times in each group.
Note: the starting position is in the front or back of the body, so that the muscle fibers of deltoid muscle can be exercised, and the supraspinatus muscle can also be exercised.