Lower back pain after sit-ups is mainly due to strain on the muscles of the lower back, including soft tissue and small joint injuries. You can take bed rest, or local use of drugs to reduce swelling and pain relief. 1. Bed rest: due to incorrect force during exercise, resulting in lumbar injury, so need to avoid strenuous exercise recently, brake rest, while walking in daily life, standing when wearing a waist cuff for protection. 2. Use of drugs: in the damaged area can be used externally some Yunnan Baiyao aerosol and other anti-inflammatory drugs, if the pain is severe, you can take ibuprofen and other pain medication, while you can massage, physical therapy and other ways to assist in the treatment. If the patient is combined with osteoporosis, lumbar disc herniation and other diseases, and rest after the pain is not relieved, it is necessary to consult a doctor in a timely manner to clarify the cause of the disease, under the guidance of the doctor for targeted treatment.