In a typical contest, football players run for a total of 10-11 kilometres at fairly modest speed, sprint for about 800-1200 metres, accelerate 40-60 different times, and change direction every five seconds or so.
http://www.pponline.co.uk/encyc/football-nutrition.html
The average distance covered by a top-class outfield player during a 90-minute match is over 10,000m, at an average speed of over 7km per hour.
http://www.brianmac.demon.co.uk/football/nutrition.htm
