According to personal physique, the intensity of using props and the guidance of coaches will affect the exercise time. The most important thing is step by step. Don't come up and practice foolishly, it's easy to strain your muscles! Personally, before exercise, you can only target the abdominal muscles for fifteen minutes at a time, and then gradually increase it for one to three minutes! If you can persist for 30 minutes at a time, you can achieve great success!