I strongly believe that that the fitness component most important to success is soccer-specific endurance: a good aerobic capacity to speed recovery from fast running.
What I haven't addressed is the "fast running" part of that statement: speed. It's a topic that University of North Carolina men's coach Elmar Bolowich suggested that I address.
In his travels, he sees many teams that make little attempt to develop speed, and he thinks players and coaches want ideas of how to improve speed.
In the mid-1950s the nature of the game changed forever when the great Hungarian national team destroyed, dismantled and wholly embarrassed England 6-3, in Wembley; a game that was not as close as the score indicated. Observers of that game commented on the remarkable speed and work rate of the Hungarians.
More on Soccer Speed Training
The Hungarians had four or five players who could run 100 meters in 11.5 seconds or less! I first started paying really serious attention to the World Cup in 1974 and read that all the field players from the former East Germany could run under 11 seconds for the 100 meters. From four or five players under 11.5 seconds to the entire team under 11. Nowadays, 11.5-second speed might not be fast enough for a good high school soccer team.
The game I see today is played so much faster than the game I played. Is that a result of a better athlete, better coaching, or something else? I would like to think it is the first two, but I also see coaches using the free-substitution rule to encourage players to run as fast as they can get tired and then be pulled for a rest.
So players have the mindset to sprint whenever they are on the field. If you have watched recent NCAA men's finals, you have seen teams that try to play at a high pace all game versus teams that play a more controlled pace and use speed selectively, like past winners Wisconsin, St. Johns and North Carolina.
Speed is an elusive creature. Is it innate or can it be developed? What goes into the concept of speed? The first player to the ball may not be faster than the opponent; some people just consistently get there first.
The great Larry Bird of the Boston Celtics was never to be confused with a sprinter, but he always seemed to be in the right place. Was it speed afoot or speed of thought, or both?