For all the talk of tactics, team selections and star performances, injuries - and their management - are the decisive factor in performance.In football there is a strong correlation between players used versus finishing position in the league table - the fewer you use, the higher you finish (Leicester City are on course to confirm that in England this year).Yes, winning teams also make fewer changes for tactical reasons, but many major sporting competitions now have comprehensive injury surveillance studies, in which teams declare all injuries that have caused players to miss practice and matches; and they show that the best-performing teams tend to suffer fewer losses to injury.The ability to keep a relatively small group of players on the field as much as possible makes an enormous difference over the course of a season.That's not a luxury often afforded a Super rugby coach.For example, the Sharks lost their second match in a row this weekend, but also lost at least two players; first, Stephan Lewies before the Lions defeat, and then Marcell Coetzee during the match. They will now have to travel (another stress) to New Zealand for a tough string of games while juggling current and likely future injuries.The Stormers have lost so many backline players that they might be forced to select their flyhalf from the Pinelands Boy Scout troop (though Jean-Luc du Plessis made an encouraging start as their fourth fly-half of the season against the Sunwolves).They're also down two locks - Eben Etzebeth and Jan de Klerk won't miss the entire season but they're out for a substantial period.And perhaps the most high-profile injury so far happened before the season even began, when the Bulls lost their first-choice flyhalf, Handre Pollard, for the entire year, when he ruptured knee ligaments during training in February.Frustratingly, Pollard's injury, as well as those to Kurt Coleman and Dilyn Leyds, were knee ligament injuries in training and not because of contact.So was Etzebeth's calf injury. Around 50% of injuries happen in tackles, with high speed sprints and collisions the next-most common causes of injury.And so you accept that the matches will produce injuries.Throw 30 highly conditioned, big men onto a field for 80 minutes of full contact and there are bound to be injuries, some severe, some less so. But when you lose star players in relatively innocuous ways like practising passing or lineouts, that's harder to swallow.On average, there are three injuries per match, which means each player has a one-in-10 chance of getting "unlucky".If even one of those three is severe enough to force a player out for two weeks, a team will permanently have two players on the injury list.In reality, there are more long-term injuries (ask Pollard, Etzebeth, Coleman). That's why successful squads must have cover in every position - with 20 matches a year, every positional group on the field - front row, loose-forwards, locks, wings, centres - will experience at least one injury that costs a player two weeks on the sidelines.Preventing these match injuries is no simple task. Conditioning work to prepare players for the physical demands is a key part of it, which is why work done in the off and pre-season is so crucial. It's also why the debate about playing too much never goes away - playing more matches not only means more opportunities to get injured, but also less opportunity to recover and regain strength and balance to avoid many of the injuries.Teaching better technique helps, because injuries happen, on average, when tackles are relatively poorly executed. Whether this would make a difference in the frantic, high-intensity battles of Super rugby is questionable.Ultimately, there's a little luck involved, but a great deal of planning and preparation, not only to keep the risk down, but to have plans in place to survive the inevitable.The next seven weeks will test those plans, and the last team standing will in all likelihood find itself riding high atop the conference tables...