You should hold a stretch for as long as it does not become too painful for you. Stretch as much as your body needs but not too much because, it could tear up your muscles and tendons. This is the best answer i could give you.
Answer: If I had a kid that was 13, I would say No
Explanation: I think no, because I would be to scared if something would happen to him. Plus, it’s just to be safe. Perhaps an adult can go with him to ensure he’s safe. Hope this helps -Bella
heredityEach offspring is a combination of its two parents, receiving some dominant traits from its mother and others from its father. Encyclopædia Britannica, Inc. Because genes are integral to the explanation of hereditary observations, genetics also can be defined as the study of genes