The side lift is mainly aimed at the middle bundle of the shoulder. If the trapezius muscle is sore and the middle bundle is not obvious after training, it is probably a mistake, so correct your movements first, pay attention to not completely straighten your elbow when raising your arm, bend it slightly to prevent the arm from relaying, and then stretch your hands forward a little bit, not completely at your side, which can also prevent the trapezius muscle from relaying.

Secondly, pay attention to the relaxation of trapezius muscle when doing actions. Although trapezius muscle will be involved more or less, it should be involved as little as possible, so relax your trapezius muscle. If you can't do it, you can let your friends touch the trapezius muscle behind you. If you work hard, I will remind you. At this time, you can relax a little and do it a few times more, which will improve.

Finally, pay attention to the weight of the side lift. Generally, trapezius muscle will relay when its weight exceeds its tolerance range, so choose a lighter weight. Besides, shoulder training does not need a lot of weight, mainly from multiple angles. Choose the right weight and do it several times in each group.