2. Pain, the pain caused by lactic acid accumulation is generally manifested as a regional feeling, while the pain caused by injury will be manifested as a punctate or linear feeling.
3. Stretching, the aggravation of pain caused by lactic acid accumulation is not obviously tolerable during stretching, but the pain caused by injury will increase sharply during stretching.
4. Duration: Generally, the pain caused by lactic acid accumulation will be relieved or disappeared within 48-72 hours, while the pain caused by trauma will last for 4 days or more if it is not handled properly.