One of the misconceptions about elite sport is that great athletes have nothing in common with normal human beings. Instead they are seen as supermen who have risen above the flaws and anxieties that define the lives of others. The superman delusion also distorts how we think about teams. When a team establishes a dynastic supremacy, instead of recognising that it is always in a state of flux, we pretend it has a stable collective personality. We turn the team into a superman.

A winning team does not, in fact, require everyone to play well all the time—or even any of the time. Sir Alex Ferguson struck a deep truth when he said that in football you only need eight players to perform well to win. In his quarter century at the top, Ferguson added, all 11 players had played well simultaneously in only six matches. So even one of the greatest sports teams carried a few players in almost every match.

Eight out of 11: Ferguson may be setting the bar characteristically high. A glance at other sports shows how much can be achieved by a high-performing core. In 2012 half the European Ryder Cup team (Donald, Garcia, McIlroy, Poulter, Rose and Westwood) contributed 78% of their total points. The "Miracle at Medinah" was one of the great team comebacks, but the burden was not borne equally.

It is also a myth that every champion team is made up exclusively of champions. We have all succumbed to the idea at some point: Australian cricketers have combative flintiness in their DNA; Germany always finds a way to win; Yankees pitchers are cut from a different cloth; no All Black would ever make that mistake. In a period of dominance, it is easy to assume that players in those teams are superior by definition—and that players in lesser teams, also by definition, were frail and unreliable. In the midst of one England batting collapse, a sports editor asked me to write a piece explaining "why England batsmen get out playing weaker shots than the Aussies". I replied that Australians played bad shots too and there was no good way of losing your wicket. The crucial question is how often you play the wrong shot. Character is revealed in frequency of mistakes, not in the mistake itself.

The reality of team dynamics is much more subtle and interesting than superman theory allows. All teams, even the greatest, include a range of characters, not all of them psychologically bulletproof. There are those who surf the wave as well as those who turn the tide. And in losing teams there are players of unflinching mental fortitude who suffer only from the misfortune that their toughness is obscured by a lack of class around them.

From a management perspective, the challenge is to establish two distinct but overlapping majorities: a majority of strong characters who have the ability to carry people with them, and a majority of players in form on any given day. Seen in that light, winning becomes partly a matter of probability. If you have a higher proportion of excellent players, who are likely to be in form more often, then the odds of eight playing well next Saturday inevitably improve. Belief, of course, is also always part of the equation. When I was captain of Middlesex, I would try to end team talks, especially those that followed a defeat, with a simple injunction: "Whatever you do between now and the next game, whether you practise or rest, make sure you drive into the ground on match day believing you are the player who is going to win the match for us."

A subtler kind of majority is also needed for long-term victory: a core of team-spirited players. The story of good teams is really the story of good senior players (who don't have to be old, so much as resilient and reliable). They set the tone, the culture. Does the team search for excuses or look within itself for the solution? Do team-mates support each other or turn against each other? Can the captain and coach rely on loyalty and support when it matters? The answers are determined by the handful of senior players who set the agenda in every team.

It is another myth, however, that good coaches and captains have the capacity, or even the inclination, to get everyone on board. Instead of dreaming of perfect loyalty from everyone, effective leaders often make the opposite calculation. Given that there will always be one or two intransigent sceptics, it’s better to focus on players who you can bring into your camp. "You never have everyone," the best coach I played under told me, "but instead of wasting your time on the one or two determinedly difficult characters, turn your attention to the two or three waverers they take with them." It's very hard to lead a team with only half the players on side, but it's possible with eight or nine, and a couple yet to be convinced. Forget unanimity, seek a quorum.

A team of 11 needs six or seven big figures to drive the group dynamic with their ability and willpower. The great Australian cricket team of the 2000s had McGrath, Gilchrist, Ponting, two Waughs, Warne and Hayden. The England rugby XV that won the 2003 World Cup had a spine of nine players—including the whole of the pivotal back row—who all played more than 65 times for their country.

A magic winning ratio of roughly two-thirds: isn’t that another incarnation of Fibonacci’s golden mean?