After tough workout or a day full of physical activity, it's common to find your muscles aching, but where do these pains come from? According to a German professor, the soreness comes from straining your muscles in an uncommon way, for example, jumping on a bicycle for a ride, because you haven't ridden in a long time. Soreness occurs since your leg muscles aren't used to that movement. When muscles perform an activity they aren't regularly expose to, the tiny fibers that are inside them are being torn apart. As muscle soreness develops, the body has to work to repair the muscle tears, but this doesn't happen immediately. First, the body must realize the muscles are damaged. When the body realizes the muscles are hurt, the response is to increase blood flow to the area and increase body heat, damaged cells are then cleaned up and the body sends cells specially designed to break down the large muscle fiber fragments. Healing can take place after this. It takes about a day until these cells make it to your aching muscles. That's why there is most often a delay associated with muscle soreness. Repair of damaged cells takes about two days, and afterwards the soreness disappears. Unfortunately, there is little that can be down to relieve muscle soreness. Pain relieving creams don't work, but a hot shower, or warm bath can provide some relief.

Questions 22-25 are based on the passage you have just heard.