Who Were Arsenal's Two Footed Marksmen ?

Picking the ball up wide left, your new signing races off down the line, rapidly slowing as he's engaged by a covering defender before a stutter step sees him cut inside his opponent giving him an unimpeded route into the box. The keeper meets him ten yards from goal, but with the added protection of a narrow shooting angle. Deliberately, your player opens up his body shape, before curling an exquisite right footer chip wide of the keeper's outspread arms and just inside the angle of post and bar. Everyone's delighted, the manager, the players and most importantly, the fans. And then it hits you....the expensive new signing can't kick with his left foot.

Favouring one foot over another is a well known facet of football, anyone who's played football at any level will well recognize that it feels more natural and easier to kick with one foot, usually the right, than the other. It's also well documented that continued practice does enhance your ability to perform a task. Therefore you would expect professional players to be able to overcome the seemingly natural preference for one foot over the other and reduce the ability gap between feet through constant repetition.

Many players are listed as either left or right footed, tacitly acknowledging that an ability defined preference exists. So it would be an interesting exercise to see to what extent players default to their natural side when attempting to perform actions that require skill and precision and how and by how much their competence falls away if they attempt a similar skill with their weaker foot.

The more extreme the spread of a particular talent within a group, the more pronounced the difference is likely to be between preferred and shunned feet in individual players and so shooting ability is a prime candidate to test. Martin Keown, in his newspaper column late last year highlighted the improvement he has seen in Robin van Persie's right foot. From arriving at Arsenal in 2004, in Keown's opinion the Dutchman had progressed from being almost exclusively left footed to become a genuine two footed goal scoring threat.

Preference should be very easy to demonstrate. While some split second chances will require a player to hit the shot with the foot it falls on, more often a player has time to work the ball onto his favourite side and dead ball attempts are almost universally taken with the "good" foot.

A Rare Pedidextrous Sportsman.

Five Arsenal players took a substantial number of shots at goal in 2010/11 and while it is entirely possible that none of them will still be at the Emirates come kickoff 2012/13, they provide a reasonable large sample to test for "footedness". Nasri, Fabregas, Arshavin, Walcott and van Persie comprise the group and together they attempted over 350 shots at goal and just shy of 80% of those were made with their designated "good" foot. Each of the five players shot more with their natural foot and indeed if Rosicky and Wilshere were added to the mix the lopsided nature of the splits would have been even more pronounced. Rosicky had 24 attempts on goal, of which 23 were with his right foot. His sole left footed effort was blocked at Molineux. Wilshere was even more extreme with 25 left footed shots compared to another sole, blocked right foot one.

The element of choice makes these findings unsurprising, although the apparent fanaticism of Wilshere and Rosicky for one foot may be surprising. Injury has unfortunately meant that the former hasn't kicked a ball in anger at all this season and Rosicky merely equaled his 2010/11 left footed tally in 2011/12. Of more interest is how effective were each of the five Arsenal stars who were prepared to shoot with either foot.

Once again I've used this model to estimate how likely a shot is to result in a block, a goal or a shot on target. If we compare the expectancies with reality, while accepting all the usual caveats concerning sample size and model accuracy, and split the sample by "good" and "weak" feet we can perhaps see how much drop off in production occurs between the two.


The Two Footed Robin van Persie, 2010/11.

v Persie,Left Foot (69attempts)	Goals.	Shot on Target.	Shot Blocked.
Expectancy From Model.	6.6	23.8	16.8
Actual Number	12	30	10
v Persie,Right Foot (13 attempts)	Goals.	Shot on Target.	Shot Blocked.
Expectancy From Model.	1.9	5.4	2.8
Actual Number.	5	8	1

There certainly appears to be tentative evidence that supports Martin Keown's visual opinion that van Persie is comfortable with either feet in his later Arsenal career. It's easy to be seduced by one outstanding goal with a player's weaker foot into believing that it represents a more general improvement, but Keown's judgement appears sound. Van Persie has an understandable preference to shoot with his natural left foot and he is well ahead of the model's prediction for an average shooter. His shots produce more goals with either feet than an average expectation once shot origin is considered, they are also more accurate and less are blocked. That van Persie is a better than average finisher is a given, but he maintains his superiority regardless of the foot propelling the ball.

The Not So Two Footed Andrei Arshavin, 2010/11.

Arshavin,Right Foot (49 attempts)	Goals.	Shot on Target.	Shot Blocked.
Expectancy From Model.	3.6	15.7	12.4
Actual Number	5	19	8
Arshavin,Left Foot (21 attempts)	Goals.	Shot on Target.	Shot Blocked.
Expectancy From Model.	2.1	7.7	4.6
Actual Number.	1	7	5

The evidence is less compelling in the case of Arshavin. He's above average in terms of goals, shots on target and evading blocked efforts with his favourite right, but below the line in all three categories with his left. These more ambiguous results continue as we move through Arsenal's midfield from 2010/11. Walcott posts van Persie like figures with his right boot, but is only just above average in accuracy and output with a left boot that positively attracts blocks from defenders. Nasri partly mirrors Walcott's performance and Fabregas was a slightly below average shooter with his preferred right and even more disappointing with his weaker left over his last season with the Gunners.

Individual player numbers hold more headline grabbing interest than generalisations over a larger group, although the former are often less reliable and the latter prove to be more predictive. Therefore, it seems sensible to combine the data from our group of numerically prolific marksmen in an attempt to gauge the size of the difference between feet.

Arshavin, Walcott, Nasri, Fabregas and van Persie Efforts Combined & Sorted By Preferred Foot.

Arsenal 5,Preferred Foot.(291)	Goals.	Shot on Target.	Shot Blocked.
Expectancy From Model.	23.3	96.7	74.8
Actual Number	34	112	66
Arsenal 5,Weaker Foot.(76)	Goals.	Shot on Target.	Shot Blocked.
Expectancy From Model.	8.2	28	17.4
Actual Number.	11	34	21

We've already seen that there exists an 80:20 split in shot numbers and shots by the group's stronger feet outperform average predicted scoring rates by over 45%. This shouldn't surprise, at the moment to maximize numbers, the model comprises shots by strikers, midfielders and defenders and we are dealing with Arsenal's elite scorers here. Shots with the weaker foot only outperform the goal model by 35%.

Accuracy is similar in both subsets, but significantly less shots are blocked when players shoot with their natural foot compared to their unnatural side.Speculatively, this may because "wrong" foot shots lack power, giving blockers more time to intervene. Certainly, there is a reluctance to shot from extreme distance with this group's weaker foot, perhaps an admission that such attempts are likely to be fruitless. Shooting distance averages 16 yards in this weaker category, but extends to over 20 when attempts are made with the stronger foot.

Overall, the limited data would appear to confirm intuition. Players have a weaker foot and it should be possible in time to estimate the size of this deficiency for different player positions, given more extensive data. The individual splits suggest that some players are able to improve their weaker side and partly bridge the performance gap, while maintaining a preference. This may make them more unpredictable when faced with a shooting opportunity and consequently more dangerous.

In his Arsenal career so far, Tomas Rosicky virtually never shoots with his left boot, so only he knows how good or bad his unfavoured side is. Maybe he should be prepared to use his left more frequently before his predictability becomes common knowledge in the EPL.