Pull-ups are mainly used to exercise biceps, and the effect is not good. If you want to increase your arm strength, I suggest you add a few exercises, such as putting a dumbbell on your back (gravity can be light or heavy), sprinting your left elbow on your left thigh, keeping your right leg straight and raising your right hand to shoulder height! ) pectoral muscles, (this is generally known! It is recommended to clap your hands on your back, that is, clap your hands in the air when you get up. If you can't, just use the ordinary one! Triceps, (also with heavy objects. Hold the weight behind your head with both hands, bend your hands to make them straight, and repeat the exercise. This action must be standard and cannot be pushed to the front. That won't do. Be careful! Finally, the shoulder muscles, (lifting heavy objects with both hands, the feeling of squeezing and contracting your shoulders is the same as touching your ears with your shoulders, you can't touch them without trying! ) Muscles are connected. The strength of one muscle and two muscles is not necessarily great, but once the muscle group becomes stronger, the strength will increase geometrically!