The strength of the core is crucial to the runner's body and running performance. If the core muscle of a runner is not strong enough, it will increase the risk of lower back pain, muscle tension, insufficient balance, incorrect running posture, and the final result will be injury. Through core training, runners can enhance muscle strength and stability, effectively prevent injuries of knee, hip joint, lumbar spine, lower back and other parts, and help better maintain running posture and improve running efficiency. In the training of strengthening the core, including sit ups, hip bridge, flat support, etc. Among them, flat support is one of the most effective and simple training items. The following four plank support exercises are all typical plank support actions. Before practicing, warm up by jogging or walking and slight stretching. Then do each exercise twice, a total of about 5 minutes. After a period of time, you can see the effect. 1. Straight arm flat support: first put the posture of push up, and stretch the arms to support the body, slightly wider than the shoulder. The hands are located directly below the shoulders, the core part is tightened, and the back side of the body is kept in a plane, especially the hips can neither rise nor sink. Hold this position for 30 seconds. If you want to reduce the difficulty, you can use your knees to support your body. 2. Sit on the ground with your legs straight in front of your body, put your hands behind your body, and open your fingers to touch the ground. Then use both hands to lift the body up gradually. The final posture is that the arms are extended to support the body, the legs are also extended, and the front side of the body is kept in a horizontal plane. Hold this for 30 seconds. If you want to reduce the difficulty, you can bend your elbows to support your body. 3. Side type flat support: first lie on the ground with the right body, and the right elbow is bent directly under the shoulder to support the body. Keep your legs straight, your left leg above your right leg, and your feet together. The head and spine are in a natural state, and the right hip and knee are in contact with the ground. Then, use your core to lift your hips and knees up off the ground. The left side of the body is in a straight line. After holding this position for 30 seconds, do the same action on the other side. 4. Pyramid type flat support: firstly, the body is supported by the forearm to pose as a flat support, then the core part is tightened, and the hips are gradually lifted up until the body presents an inverted V shape. After holding the posture for a few seconds, return to the original posture. This workout also lasts 30 seconds. After the above training is completed, repeat it again. It is very useful for runners with tight time. It takes about 5 minutes every day to train a strong core. (outlook new era)