1, "heavy shoulder" is not made of shoulder muscles at all, but of scapula muscles. We often shrug our shoulders in training because the scapula is not stable enough. When we are doing movements, when we contract centripetally, that is, when we press down, we can lift the shoulder joint by shrugging to shorten the contraction distance, which makes it easier to complete the movements (share the strength of latissimus dorsi). When we centrifugally contract, if we directly restore the latissimus dorsi muscle, then we can lift our arms after shrugging, and then we can resume shrugging, so that the action is broken down into two parts, which is also a kind of compensation.

2. From the first third of the superior nuchal line, occipital protuberance, nuchal ligament, spinous process of the seventh cervical vertebra, all thoracic spinous processes and supraspinous ligaments. It is divided into upper, middle and lower bundles, the upper bundle ends at the lateral third of clavicle, the middle bundle ends at the lateral acromion and the upper edge of scapular ridge, and the lower bundle ends at the upper edge of scapular ridge. The function of the upper bundle is to lift, rotate and contract the scapula; The function of the middle bundle is to contract the scapula; The function of the lower bundle is to make the scapula sink, retract and supinate.

3. When doing back muscle training, you need to "sink your shoulders", which are mainly pull-down and paddling. For example, when doing a pull-down, it is easy to shrug your shoulders (that is, raise your arms up) during the centrifugal stage. The general advice of fitness instructors is to let your shoulders sink, not shrug.