Because you could be a mere 100 lbs and still have a high body fat ratio. Transversely, you could weight 300 lbs and have a low body fat ratio.
Hope this helped :)
A.Nylon because nylon is a chemical that is bad if you put it on your skin when it's cold
Well what is your side of it first
Prevention of injury in young footballer may include:
Regular health and wellness assessment
Adhering to warm-up and cool-down regime
Adequate intake of water to maintain hydration
Doing strength and stretching exercises
Wearing fitted protective equipments like pads, helmet and mouth-guard
Consulting physiotherapist or sports medicine professional, whenever there is an injury.