How do I get my endurance up?

How do I get my endurance up?A common question and problem,all players should be able to run their hardest for the full game, but how does it happen?Well,Soccer Maniac's Site has the answer.One way you get tired is through cramps,cramps are caused by muscles getting tied and too tight together.So you notice how people with six packs have each muscle visibly lined up.That is the basic idea behind this.To not get a cramp you should do about 30 sit-ups and 20 leg lifts and day so your muscles don't get tied up.The second reason you could get a cramp is your muscles getting tired.So really the best way to help that is to run every day and try to improve on yourself.