Sports are very important for everyone to stay fit and living a healthy life. Sports keep a person mentally healthy and proves the saying of "healthy mind lives in healthy body". Sports keep a person relax and also imporves social health. Sports such as running and other exercises keeps blood circulation good. Not only outdoor games keeps us healthy but also indoor games are healthy for our body. Sports are very important for kids and helps in their growth process, good health and fitness. Several games such as Olympic games are organised every year to support sports and promote fitness all around the world.
The best test would be a BMI. Hydrostatic weighing would just find their weight and wouldn't tell the doctor anything about the specific amount of fat on the body. There is no such thing as an MRK, and the Caliper test is a personality test. I hope this helps!