Why do Arsenal score more headers than every other Premier League team?

It is a curious quirk of the past two seasons that Arsenal rank top of the Premier League for headed goals given the type of team they are supposed to be.

Arsene Wenger's team lack "cojones", according to Troy Deeney and that, he said, was the reason Watford were able to come from behind to win last weekend's encounter. For years Arsenal have been said to be too meek, and struggle against physical sides.

And yet, at the other end of the pitch they are more effective than any other side, scoring the most headers this season, having done exactly the same last season, too. Doing so in one season could just be a slightly unusual anomaly, but a second successive season points to something more significant at play.

First off, there is the obvious answer: a big, red, bearded French thing that Wenger sometimes sticks up front.

Olivier Giroud is patently the biggest aerial threat in Arsenal's squad. He is perfect for a team that so often comes up against two deep banks of four, clinging on at the Emirates for a point.

Graphic: Most headed goals scored

During the time in which Arsenal lead the Premier League for headed goals, Giroud is joint-top in the individual rankings, along with Romelu Lukaku, Christian Benteke and Fernando Llorente, having started just 11 games in that period. The other three players have 44, 42 and 28 starts, respectively.

Indeed, it is from the bench that Giroud is so effective: all seven of his headed goals since the start of 2016/17 have been scored in the last 15 minutes of matches, and five of them have come after the 85th minute. Only one Arsenal header has been scored by anyone else after the 76th minute in the last two seasons (Alexis Sanchez vs Sunderland in May). In the Europa League on Thursday night he added another late goal (though this one wasn't a header).

Giroud tops the heading charts

Premier League starts

He is a handful at the best of times, but becomes extremely difficult to hold down when defenders have already played the majority of a match and he is fresh.

He is so effective, in fact, that only the Premier League's all-time leading scorer, Alan Shearer, can match Giroud for headers scored in the final 15 minutes of matches since football 'began' in 1992. Shearer made 441 appearances; Giroud has well under half that number.

Headed goals in last 15 mins of matches

All that said, however, if you take away Giroud's contribution, Arsenal remain a formidable force in the air.

Subtract his seven headed goals from Arsenal's total since the start of last season, and his team still rank second in the Premier League, with 15, behind only West Brom. Giroud has only scored one of their five headers this season. There is more to Arsenal in the air than their most obvious asset. So, what is the secret?

Their many technically gifted passers of the ball are exceptional at creating space in advanced positions, and that leads to more opportunities for more measured crosses than other teams attempt. Only four teams average fewer crosses per game since the start of last season than Arsenal's 17.7, but their crosses are rarely lumped into the box from deep; instead they forge chances to cross from nearer the byline, with tucked in forwards creating space for overlapping full-backs (or in more recent times, wing-backs). When Arsenal do bother to cross the ball, they generally do so from a better position than other teams.

Then there is the magic (and grossly underappreciated) left boot of Mesut Ozil. Unsurprisingly, Ozil is the top Arsenal 'assister' of headed goals since the start of last season, with his in-swinging cross from an inside-right position extremely effective.

Finally, the threat Arsenal pose at set-pieces is largely underplayed. Giroud, Per Mertesacker, Shkodran Mustafi, Laurent Koscielny, Danny Welbeck add significant height to the Arsenal team and perhaps it shouldn't be a surprise that they score so many headers.

Could it be that teams do not prepare as they might to face Wenger's team because Arsenal don't have a reputation as a team that is dangerous from corners and free-kicks? 

Tom Cleverley marking Mertesacker for the German's goal at Vicarage Road last weekend was pretty hard to understand, particularly for a manager as studious and meticulous as Watford's Marco Silva.

But credit should also be given to Wenger for doing extra work to make the most of set-pieces, an aspect of the game with which he has never before been associated, and is often criticised for neglecting. Silva may well have prepared his team properly for the game, but Arsenal had something else up their sleeves at the corner from which Mertesacker scored.

At the other end, too, Arsenal have tightened up at dead balls. Since the start of last season, Arsenal have conceded 15 goals from set-pieces, which is nine fewer than champions Chelsea and the same number as Tottenham, who have the best defensive record in that time.

Clearly, Arsenal's aerial prowess is no coincidence. It is an area of their game that Wenger has sought to improve in recent years and his work and recruitment has brought reward. That is one thing, at least, for which Wenger and Arsenal should be given some well-deserved praise.