Isometric contraction of the muscles is very important and one of its main effects is to promote venous return to the muscle tissue around the fracture. Because the muscles are painful after the fracture, the actual amount of muscle activity is relatively reduced at this stage, although the limb will also have some activity, and the venous return will slow down at this time. The slowing down of blood flow in the local muscle veins makes it easy for platelets to gather and form a thrombus. As we all know, once the thrombus is formed, it is very scary, where the thrombus falls from the blood vessel wall (falls down, drifts with the blood vessel wall, and may be tethered there when it reaches the narrow place), where it is embolized, most commonly causing heart attack, brain infarction and pulmonary embolism. In addition, fracture patients are bedridden after surgery, which is equivalent to the loss of gravitational stimulation of the limb bones, which makes them very susceptible to calcium loss. And isometric contraction exercises can be done even after the fracture has not been given a fixation. Why? Because when doing isometric contraction exercise, the joints are not moving, and the muscles are contracted statically, we have a saying that “shitting and clenching fist is secretly hard”, this is the feeling. This time can be good to promote venous reflux, prevent the formation of venous thrombosis, while giving the bones and joints a certain force stimulation, can prevent calcium loss. Therefore, it is very important to do muscle isometric contraction exercises. All post-operative fractures are painful when moving the joints, and we require that this pain must be within the tolerable range; the 21st century is still about humanistic care. Pain is a great stimulus to the body, and it is not good to continue to increase the pain through exercise when it is already painful. So, what to do? We have a saying, must be within the range of pain tolerable exercise. For example, weight-bearing exercises for the lower extremities should be performed at WBAT (Weight Bearing Tolerance – the weight the patient can tolerate through the lower extremities). Also if it is particularly painful, it can be very helpful to use some NSAIDs.