If the purpose is to reduce fat, it is better to do anaerobic resistance training of instruments first, and then aerobic training, and the effect will be better. Generally, the jogging speed can be set at 8 to 8.2, and the slope 1, so that the burden on the knees is less. Instead of running for 40 minutes at a time, you can run intermittently, 10 minutes 8.2, 2 minutes 5.5, and walk fast, one cycle. Remember to stretch and warm up before running, and stretch your bones and muscles after running to avoid injury.