The efficacy and benefits of crunches include strengthening the abdominal muscles, improving digestion, and increasing endurance. 1. Enhancement of abdominal muscles: sit-ups can effectively exercise abdominal muscles, increase the strength of abdominal muscles, and achieve the purpose of weight loss and bodybuilding. 2. Promote digestion: sit-ups are good for gastrointestinal movement, which can promote digestion and prevent constipation. 3. Enhance endurance: daily sit-ups, and can maintain a certain exercise frequency, can exercise and enhance the human body’s endurance and physical and mental fortitude. Although sit-ups have a lot of efficacy and benefits, but still need to moderately adjust the amount of daily exercise, especially the lumbar muscle is not good patients, remember to moderation and behavior, so as not to cause unnecessary injury, can exercise is recommended to consult a doctor in a timely manner.