The inability to straighten the arm after lifting dumbbells is mainly due to excessive exercise, excessive exercise load, and muscle damage to the arm, resulting in dysfunction. There are two cases: 1. Mild muscle damage can be caused, and when the patient is inactive, there is no obvious pain, but only when the arm is straightened, and the patient is afraid to straighten the arm because of the pain. 2. The patient may experience pain at rest, and when moving the joint, there may be weakness in the joint, extension, etc. Patients are advised to take rest and not to continue exercising. They can elevate the affected limb to promote swelling, reduce local inflammatory stimulation, and reduce local tension, thus reducing pain. Observe for a period of time, and if the symptoms do not return, be sure to go to the hospital for consultation.