There was a time when Carlisle United's results and performances seemed to reflect the fact they were under the management of a former winger. Dynamic going forward, but loose at the back. Good to watch, but they'd give the old nerves a workout.

That time is now. Keith Curle was not originally a centre-half, but a wide player unsure of how best to exploit his remarkable pace. "He was the quickest thing I'd seen," said his mentor at both Bristol clubs, Clive Middlemass. "Really quick."

It was Middlemass who helped convert Curle into the position where United's boss made his name. And now Carlisle can't seem to stop conceding, the fact Curle was a defender is perplexing some.

He played hundreds of games there at the top level, and three for his country, the thinking goes - so why can't he sort United's back four?

It sounds logical. But it is too simple an answer to a problem that is more complex.

As a captain in his playing days, one would expect United's boss to carry a certain natural authority. And yes, as a defender of high standing he should be able to pass on certain things.

But unless Carlisle's back four also includes a young Keith Curle - incredibly fast, suited to playing alongside a more traditional warrior - the effect of that specific experience may be limited.

Instead, a manager must go deeper and broader. Building a team, coaching it, setting its strategy, steering it through choppy waters: these areas call for detail and expertise that go beyond simply reminding his players to mark up at corners.

Curle last played as a top-flight defender with Manchester City in 1996. Since 2002 he has managed five clubs and worked at two others. None of these employed him purely as a defensive coach and so, over 15 years, United's boss has been more concerned with developing players and teams generally, rather than focusing on one specific department.

This not to say he has nothing to teach anyone about defending. But the fact he has at times encouraged Carlisle to play attractive and risky football - and with generally good results this season - should remind us not to put people back in old pigeon-holes long after the event.

If it was as simple as appointing a former defender to preside over a solid team, Tony Adams would have had a long and distinguished managerial career. He rose to prominence in the Arsenal of George Graham, and is widely regarded as one of England's best modern centre-halves. Didn't stop Wycombe or Portsmouth losing their fair share, though.

Speaking of Graham, where was it in his DNA that he would go on to manage a team where a particular scoreline (1-0) would become its motif? He began as a centre-forward and was later a midfield playmaker. His rigid mastery of a team's defensive side only emerged later.

Players change, or are often more complex than they first appear. One of Carlisle's most stubborn recent teams, the title winners of 2005/6, kept 20 clean sheets in 46 league games, guided by a former attacking midfielder with a wicked left foot (Paul Simpson).

In other eras, by contrast, an illustrious ex-goalkeeper (Harry Gregg) was unable to prevent United shipping 78 goals in 1986/7. Later, the leaks of 2012-13 could not be stemmed by a former battling midfielder or full-back (Greg Abbott). Graham Kavanagh was a fine and dynamic midfielder with more caps than Curle, but could he make Carlisle more creative during the collapse of 2014?

Aidan McCaffery was a central defender. Roddy Collins a centre-forward. Mick Wadsworth's playing career was brief in comparison but as a coach and an educator he constructed better back fours and attacking lines at Carlisle.

This isn't to say defenders can't become clean-sheet experts as managers. Or that strikers in the dugout can't teach teams to score for fun. Of course they can. But only as a small part of what needs to be a wider plan and "skill set" (a favoured Curle term). Tony Pulis' long-standing reputation for rigour may be less to do with his being a defender than the fact he took his first coaching qualifications at 19.

In non-league, meanwhile, one of the best defensive records is currently enjoyed by someone who was such an attacking free spirit that his boss at Crystal Palace sometimes allowed him to play head-tennis while others were learning set-piece drills.

If Matt Jansen managed as he played, Chorley would win most games 6-3 in Conference North. Instead they have conceded just 20 goals in 25 games. Jansen has developed different skills as a coach, and why shouldn't he? Why typecast someone without considering they might be willing to change, adapt, grow?

In Curle's case it may surprise those closely acquainted with his playing past to know that his Carlisle team scores for fun but also ships plenty. Yet if Curle has decided to make his teams more intrepid, to run the risk of conceding because the attacking temptations are simply too great, then that vision will only have formed over years of studying the game and being in many more environments than lining up next to Alan Kernaghan and Michel Vonk in the mid-1990s.

All this said, we need not park Curle's reputation in the opposite corner, either. In 2012/13, his Notts County finished the League One season with a better defensive record than second-placed Bournemouth and play-off winning Yeovil. Before his dismissal in February, Notts kept 10 clean sheets in 29 league games.

Perhaps he had better players, defensively. Maybe the message was getting across better. Or the overall blend could simply have been different and requiring of attention in other places compared with this Carlisle side, who are still third, remember.

Nobody would pretend the Blues have started 2017 positively, but we can still look at the bigger picture. Few people were showering former centre-half John McGreal with awards in the autumn when his Colchester were conceding and losing.

It took him much longer to come up with the tactics that have made them stronger, and despite some impressive form they remain seven points adrift of leaky old United who, in their better runs, have benefited from a set-piece expert who has seldom curled a cross into a box or tried to lose a marker in his life.

Yet Simon Tracey, a former goalkeeper, has still been able to impart crucial things to Curle's players in dead-ball situations. This surely means that while experience is one thing, so is having a good eye, an open mind and the niche ability to teach and instruct, as well as having players smart enough to make the most of what you are asking.

So yes, Curle needs to fathom Carlisle's defending, and as soon as possible. But that's Curle the manager, Curle the motivator, Curle the thinker, Curle the teacher, Curle the coach, and a sight more things than just the bloke who was winning headers and chasing strikers before Macaulay Gillesphey was even born.