However, there is another way to train muscles. The method of jumping back and forth, left and right is very simple. You don't have to jump back and forth, left and right, and you don't have to jump as fast and high as you can, as long as you can jump 20 times. After jumping, you will feel sore and sore in your leg muscles. Hold back and wait until the pain stops before you stand up. That's the best part. That's what we feared most when we were in the army.