(1) Upper limbs of pectoralis major: all of them start from the lateral side of the thorax and end at the upper limb with bone or humerus, mainly including pectoralis major, pectoralis minor and serratus anterior.
The pectoralis major muscle is shallow, covering most of the chest, fan-shaped, wide and thick. From the medial half of the clavicle,
At the sternum and 1-6 costal cartilage, the muscle bundles of all parts converge outward, and the flat tendon ends at the crest of the greater tubercle of humerus. Function: the humerus can be adducted and rotated;
When the upper limb is lifted and fixed, the trunk can be lifted and the ribs can be lifted to assist inhalation.
The pectoralis minor muscle is located on the deep surface of the pectoralis major muscle and is triangular. It starts from the 3rd-5th rib and ends at the coracoid process of the scapula. work
Use: pull the scapula forward and downward; If the scapula is fixed, you can lift the 3-5 ribs to assist inhalation.
The serratus anterior muscle is located on the lateral side of the chest, starting from the lateral side of the upper 8 or 9 ribs with muscle teeth, and the muscle bundle goes backwards and passes through the shoulder.
In front of the scapula, it stops at the inner edge of the scapula. Function: can pull the scapula forward, so that the scapula is close to the chest; If the scapula is fixed, it can be lifted.
Ribs, assist inhalation. When the serratus anterior muscle is paralyzed, the medial edge of the scapula tilts upward, which is called "pterygoscapula".
(2) pectoral muscle: It participates in the formation of the chest. In the intercostal space, there are mainly external intercostal muscles and internal intercostal muscles.
The extracostal muscle is located in the shallow layer of each intercostal space, starting from the lower edge of the rib, and the muscle bundle obliquely goes forward to the next one.
The upper edge of the rib. In the intercostal cartilage space, there is no external intercostal muscle, but the external intercostal membrane connecting tissues. Function: External intercostal muscle can lift ribs,
Help breathe in.
The intercostal muscle is located in the deep surface of the extracostal muscle, and the direction of the muscle bundle is opposite to that of the extracostal muscle, and the posterior muscle bundle only reaches.
From then on, the costal angle is replaced by the costal intima connecting the tissues. Internal intercostal muscles can lower the ribs and help exhale.
conventional process
Supine compression is one of the most common and effective methods to develop chest muscles. Because of different body postures, bench press can be divided into bench press, upward oblique press and downward oblique press. The main instruments used in bench press are barbells and dumbbells. To do barbell bench press, it is best to have a bench press frame that accepts bars.
There are three different ways to hold barbell bench press: the distance between hands is less than shoulder width; The distance between hands is shoulder width or slightly wider than the middle grip; The distance between the hands is wider than the shoulders, which is called wide grip distance. Different grip distances make the exercise parts slightly different. Narrow grip helps to develop triceps brachii; The middle grip distance mainly develops in the middle, middle lower part, middle sulcus and part of inferior sulcus of the lateral pectoralis major; The wide grip distance mainly develops the upper part of pectoralis major, the lateral middle-upper part and the toe joint of deltoid muscle.
Take the recumbent push as an example, the following points should be paid attention to in its preparatory action: 1. Your feet must be practical; 2. The upper back and buttocks touch the stool surface to make the trunk "bridge"; 3. The rod is located at 1cm above the nipple. If dumbbells are used, the two hand bells should be parallel to the shoulders, and the dumbbells should be placed on the parallel lines outside the shoulders near the nipples.
There are also several points to pay attention to in bench pressing: 1. Push the barbell upward with the centripetal contraction of the pectoral muscles; Falling back at a uniform speed makes the working muscles do centrifugal contraction (the effect of exercise is mainly determined by centrifugal contraction and work). 2. In the process of recommendation, the trunk of the body is always fixed on a "bridge"; Take the shoulder as the axis of motion and do work with the chest muscles. 3. When pushing the barbell up, the chest should stand up and the shoulders should sink. When falling back, the big arm moves perpendicular to the trunk and the small arm moves perpendicular to the ground. Don't "shrug your shoulders with your chest", otherwise the exercise effect will be greatly reduced;
Breathing method is to inhale when lifting light weight and exhale when pushing up. If you feel tired after lifting a heavy object or the last few times, when using the straight arm support, you should take two or three breaths, then take half a breath (that is, hold your breath), and let the barbell slowly fall on your chest. When the barbell touches, immediately push the barbell up with the contraction of pectoralis major until your arms are straight, breathe, and then take a deep breath.
When doing the upward oblique bench press, most of them use a wide grip distance and put the bar at the clavicle. When supported by straight arm, the center of barbell should be on the vertical line of shoulder joint. When pushing down, the bar should be placed at the sixth or seventh rib under the nipple. When dumbbells are used for up-tilt bench press or down-tilt bench press, the dumbbells are placed outside the chest respectively, and the fists and eyes hold the bell relatively. Beginners must master the center of the dumbbell, don't shake it back and forth, and hold it firmly.