Buy a yoga mat and lie flat. The first action is to bend your knees and let your knees touch your chest 20 times. The second action is to raise your legs together and then touch your toes with your hands for 20 times. The third action is to lie prone, with elbows and toes touching the ground, and keep your body straight or your hips slightly raised for 30 seconds. These three movements are a group and the effect is very good. Persistence is the most important thing.