FitnessDoc looks at the physiological side of football and finds out what it takes to play a 90 minute game while making some interesting comparisons between rugby and football.
Moments of truth, physiological profile and fatigue
Players make, on average, 18 tackles per match (sadly, in many cases, this also means a player will dive 18 times a match, feigning injury half the time - one of the scourges of football)
The make 15 headers per match
As mentioned, players make 100 sprints where they hit speeds in excess of 20km/h
Rugby players, on the other hand, are involved in far more "impacts", which comprise tackles, scrums, sudden stops, ruck involvements, mauls and so forth.