Keeping yourself fit and eating the correct food are two very important aspects aspects of a healthy lifestyle. They will also help you to enjoy your sport and to be successful. Your coaches, teachers and parents can all help you but you have to decide to do the right things for yourself by avoiding junk food (most of the time) and by taking lots of exercise. It´s not easy and there will be times when you fail but remember nobody´s perfect! You have to be motivated to do all this and it can help to keep a diary/record of everything you eat and of all your exercise sessions (football training, swimming, running, etc. ). The document below will give you some pointers.
Strenghtening the core (centre) of your body is very important and will give you balance and power as you run. Be careful not to overdo it and if you feel any pains ease up immediately.