Thursday, 1 December 2011

Olympic Countdown - Cycling

Are your eyes deceiving you? It’s not uncommon for researchers to give false information to their subjects to see what effect this can have, but it seems particularly prevalent when cyclists are being tested. In a recent experiment, Professor Kevin Thompson of Northumbria University used this idea to see if trained cyclists could go quicker than they ever had before over a 4,000m time trial. Using stationary bikes, the cyclists did two time trials to establish a baseline time. In the third and fourth trials, the cyclists raced against an avatar (a figure cycling) which they were told represented their baseline performance. In fact, this was only true for the third trial. On the fourth trial, the avatar was programmed with 2% more power, which correlates to 1% more speed. They found that the cyclists were up to 5 seconds faster than their baseline when racing against the accurate avatar, and up to 10 seconds faster when racing against the deception avatar. This suggests that we keep something in reserve even when we feel we’re going flat out. In another similar experiment, Dr Jo Corbett of Portsmouth University asked cyclists to race a 2,000m course as fast as possible in front of a computer screen showing an avatar of themselves doing the ride on a virtual course. On the fifth occasion they had to do this exercise they were told to race against another cyclist behind a screen whose avatar was also projected on to the same virtual course. In reality, however, they were actually racing against their own best time. On this fifth race, 12 out of the 14 participants were significantly faster in the fifth race, when they believed they were racing an opponent, even though they had been apparently completely exhausted in the other races. The difference was a final burst of speed which ensured their victory, and their average speed increased from 38.4km/h to 39km/h. It seems that competition allows athletes to dip into these hitherto untapped sources of energy. To test this idea, Professor Thompson repeated his experiment using two groups of cyclists. One group was told that they would be racing against an avatar that had either 2% or 5% more power, which meant either 1% or 2% quicker than their own best time. The other group was deceived. They were told that they were racing against an avatar that matched their best time, although in reality they were also racing an avatar that was either 1% or 2% quicker. The group that knew they were racing quicker avatars soon gave up trying to match the avatar’s speed, whether it was 1% or 2% quicker. The deceived group matched the avatar’s speed when it was 1% quicker. But 2% was too much, and they gave up about halfway through, and some ended up with a time that was worse than their best effort. And there are other ways of deceiving athletes that might eke out improved performances. Earlier this year, Dr Paul Castle and others from the University of Bedford engaged 7 cyclists in 30-minute stationary trials under three different conditions. In the control trial, the room temperature was set at 21.8°C (71.2°F). A second “hot” trial was held in a room at 31.4° (88.5°F). In the final trial, the temperature was displayed as 26.0°C (78.8°F), but was in reality 31.6°C (88.8°F), the hottest of the three. As expected, the cyclists performed worse in the hot trial (31.4°C) than in the control (4% less distance). But in the deception trial, they cycled slightly further in the time than they did in the control, even though they were actually cycling in temperatures marginally higher (31.6°) than in the hot trial. The researchers even found that the skin temperature of the participants was 0.5°C lower in the deception trial than in the hot trial. So, incorrect information from the conscious brain can lead to subconscious effects that can improve performance. But it also suggests that negative beliefs about conditions such as the weather will have a deleterious effect: if you think it’s going to be too hot or too cold to perform well, it probably will be. The final experiment looked to explain why cyclists doing, say, 40km, will generally lose speed towards the end, but will often do a really quick last 2,000m. This is when their muscles should be most tired. A team in South Africa led by Professor Tim Noakes told cyclists that they would do four 30-second trials, one 33-second trial and one 36-second trial. However, on some trials the clock was programmed to run more slowly, so they were actually doing two 30-second trials, two 33-second trials (one of which they thought was 30 seconds) and two 36-second trials (again, one of which they thought was 30 seconds. You might expect the cyclists to ride with more power initially on the deception 36-second trial compared with the informed 36-second trial. But in fact their power output was the same on both trials until the 33-second point, after which power fell significantly for the last three seconds of the deception trial. This shows again that information from the conscious brain can affect performance, this time in a negative way, overriding muscle fatigue. It seems that the subconscious brain pre-determines the amount of effort that will be required for the task. In the deception trial, it took three seconds before it realised that the expected duration had passed, and then it recalculated the intensity to a lower level for the remainder of the task by reducing the nervous stimulation to the muscles. This shows that the fatigue is largely caused by mental processes, i.e. a perception in the brain, sent from the subconscious to the conscious brain, rather than muscle fatigue. And this is why you can pick up speed towards the end of a 40km bike ride, when the conservative energy-saving policy of the subconscious brain can be overridden in the knowledge that there’s not much further to go, and a recalculation can take place. In fact the brain is constantly calculating and re-calculating the power output required (and therefore the pace) in response to the distance left to race and the cyclist’s physical state, which the brain is trying to protect. This also explains the benefits of interval training, which mixes high-intensity exercise with recovery breaks. It seems to work because you learn that going faster than you think you can doesn’t do any harm. And when you’re feeling fatigued towards the end of a race, this knowledge may also enable you to relax and keep going longer and faster than you would have thought possible. David Donner

Thursday, 13 October 2011

Train As You Play

England’s early exit from the rugby World Cup was all too predictable, especially as most of their play has been, well, all too predictable. There are the usual calls to sack the manager, sack the board, drop this or that player, but I suspect the problems with English rugby go rather deeper, and I was reminded of a story my son told me a while ago. My son went to a very traditional prep school. Both academically and in sport, the boys were divided in the elite and the rest. This produced some outstanding results, both in terms of scholarships and in winning matches. But it didn’t necessarily bring out the best of those outside the elite. Fortunately for my son, he was strong academically and a reasonable all-round sportsman. But in rugby, he was not quite strong enough to train with the elite players on the playing field. Here, the boys were drilled endlessly, so the backs could pass the ball down the line with dazzling speed and immaculate handling. Instead, my son was with the rest in the Council park, where there was very little coaching, and the main aim was to try and get them to burn off as much energy as possible. And this is how my son learned to pass the ball to his left, but never to his right. One day, however, he was told to join up with the elite players, where he found himself playing centre in a practice match. Sure enough, he soon found himself with a problem as he received a pass from his left. He couldn’t pass left as there was nobody behind him. And he could pass right because…..he couldn’t pass right. So he did the only thing he could do, which was to run straight ahead. After a few strides, he looked up to find there was nobody anywhere near him, and ran in unopposed to score a try. All the other players had assumed he was going to pass down the line, because that’s what everyone else had always done. Afterwards, the headmaster came up to him and asked “How did you learn to sidestep like that?” Of course, he didn’t like to tell him the real reason. I saw a similar look of bemusement from the England players at the end of the first half against France. Jaws open, looking at each other trying to work out what was going wrong. I suspect that the plan was to sit back, let Johnny knock over a few penalties, and wait for France to self-destruct. This wasn’t an entirely unreasonable game plan, given France’s recent history. But it was fatally undermined when we donated them a load of points at the start. (Out of all the coaching staff, isn’t there someone who knows the laws, preferably with refereeing qualifications, who can coach them how to play without infringing all the time? If necessary, get them to practise with a “fussy” referee). And when things didn’t go exactly to plan, it all seemed to fall apart. Passes were thrown to the air, to the ground, and on more than one occasion to players who weren’t expecting it. They look like a team for whom every effort has been made to make them feel comfortable, from first class hotels to rigid game plans. As soon as a side takes them out of their comfort zone, they don’t know what to do. And I think this starts early. Writing in the Sunday Times recently, Stephen Jones talks of players as young as 12 being sucked into county and then national representative sides where all the emphasis is on preparation and endless drills rather than just playing. They don’t learn the skills of probing for an opposition’s weakness because they don’t play an opposition often enough .Their play becomes blinkered and formulaic. Of course, if they were coached from a sports vision perspective, they’d be encouraged to see what’s really happening on the field, and react to it instinctively. Do we have coaches who could do that? David Donner

Olympic Countdown - Canoe Slalom

Canoe slalom provides an excellent opportunity to study the use of imagery in sport because competitors are not allowed to practise on the actual course before a competition. Research (MacIntyre & Moran 1986; White & Hardy 1998) has shown that imagery is regularly used in both training and competition by canoe slalom participants. MacIntyre, Moran and Jennings (2002) have even suggested that elite performance in canoe slalom could be related to the ability to use imagery, even though it didn’t distinguish elite from intermediate groups. MacIntyre & Moran (2207) studied 12 canoeists, all of whom had finished in the top 10 at either the World Championships or Olympics, with more than half being medallists. What was surprising was the range of things they used imagery for. As well as being used to learn the course, imagery was employed as part of their pre-race routine, to review their performance after the race, to imagine how they might overcome particular difficulties during the race, to imagine how they might adapt another competitor’s actions to their own performance, to learn new techniques, to remember previous successful performances as a way of overcoming a slump in performance, to get them in the most appropriate frame of mind, and to help when returning to the sport after injury. Sometimes, they were able to imagine what the performance felt like in their muscles, as well as having a visual image, and many felt this was an important element of their imagery. These athletes were able to analyse their imagery to quite an advanced level. They recognised hat imagery could be negative as well as positive, for instance if they imagined themselves making a mistake. But they also devised strategies to overcome these negative images, such as “re-winding” the imagery and “replaying” it without the mistake. Some athletes found that discussing with the coach their imagery of completing the course helped them to overcome negative imagery. In some sports, coaches themselves have used imagery, for instance to imagine what an opposition coach might do in a match. It may be that canoeing coaches are able to compare their image of the performance with the athlete’s. It’s generally recommended that athletes should imagine a perfect performance, but these elite canoeists were more likely to visualise an average performance as a base from which they might try to improve, or maintain performance in more difficult conditions. I think coaches in many sports could learn from this more subtle approach to imagery and visualisation. It would help obtain a more effective review of performance, as well as prepare the athlete for a variety of situations, such as poor weather, or a better than expected performance by a competitor. David Donner

Friday, 16 September 2011

Olympic Countdown - Boxing

If someone is trying to punch someone else in the face, it shouldn’t be a surprise that eye injuries are quite a common result, even with head guards. The most serious injuries are when damage to the retina occurs. Tears can lead to detachments and a lot of vision can be lost. Sugar Ray Leonard is one of the highest profile boxers who were forced to retire as a result of a detached retina. But trauma to the front of the eye can disrupt the drainage system of the fluid within the eye. Pressure can build up and the nerves at the back of the eye can get damaged in a form of glaucoma. Cataracts can also form at a much younger age than normal. Eye damage like this is especially likely if the trauma is caused by the thumb, as it fits neatly inside the eye socket. Modern gloves have the thumb strapped to the rest of the glove, but this still leaves part of the thumb protruding. Bianco et al (2004) studied over a thousand boxers, amateur and professional. 40.9% were found to have mild or moderate signs of eye damage, with 5.6% having serious eye problems. This compared with 3.1% of non-boxers who were found to have similar-looking eye problems. One idea to try and combat the problem was the invention of “thumbless” gloves. Unfortunately, they didn’t prove popular with boxers as it didn’t feel as if they were forming a proper fist. This could result in more hand injuries. Recently, however, a solution may have been found in the invention of the “hidden thumb” glove. A strap inside the glove enables a fist to be formed internally, but nothing sticks out externally. Let’s hope it catches on. David Donner

Monday, 15 August 2011

Olympic Countdown - Basketball

Several international rugby forwards have developed their handling skills by playing basketball, including Simon Shaw and Courtney Lawes. I often think that it would help goalkeepers dealing with crosses as well.

Vickers (1996) found that elite basketball players concentrate their gaze on just one part of the target, such as the front of the hoop. In contrast, the gaze of lesser players tends to wander all around the target. But there’s a problem: at some stage the ball gets in the way.

There are actually two shooting styles. In the low style, the ball is brought up and blocks the view of the hoop on release. Players with this style must get all their information before the ball blocks their view. In the high style, the ball is brought up above head height before being released, allowing the hoop to be viewed as the shot is taken. These players can get “Quiet Eye” information right up to the moment when the ball is released.

Intuitively, one would have thought that the high style would have been more effective, but researchers so far have failed to find one method to be better than the other. This could be because laboratory conditions aren’t tough enough, for instance there are no opponents.

Or it could be that both styles are effective as long as you focus on one specific part of the target, and you do it as late as your preferred style allows.

David Donner

Thursday, 14 July 2011

Another England Penalty Failure

This time it’s the ladies who’ve been knocked out of a World Cup on penalties. The usual response is to say that penalty shoot-outs are a lottery, and that it was just cruel misfortune. This time, however, manager Hope Powell blamed some of her players, accusing them of “cowardice”.

I have to say both responses are completely inappropriate. Taking and saving penalties are skills, like every other part of football. The secret of dealing with penalty shoot-outs is to prepare the players for the stress involved, so that they maintain the correct technique. You won’t be surprised to learn that the correct technique is all about vision, but more of that later.

Earlier on in the tournament, a BBC reporter had asked the manager if she was considering making any changes to her team for the game against New Zealand. Powell replied by saying this perfectly reasonable question was “ridiculous”. This struck me as a response of a manager feeling under pressure, and if that sense of anxiety communicated itself to the players, I suspected we were going to be in trouble.

I was also surprised to read this quote on the FA website from the manager after the France defeat. “We thought we had a chance with penalties because we’ve been practising and Karen Bardsley has been saving every single one”. Well, that might have done wonders for the goalkeeper’s confidence, but considering that a well-struck and directed penalty should be unsaveable, it clearly didn’t do much for those taking them. No wonder they weren’t rushing to volunteer.

There’s no doubt that taking a penalty for your country can be a very stressful experience. Here’s Steven Gerrard talking about his miss in the 2006 World Cup. “Jesus, I wish I was first up. Get it out of the way. The wait’s killing me…….Why do I have to wait for the bloody whistle? Those extra couple of seconds seemed like an eternity, and they definitely put me off”. Or Gareth Southgate in 2003 “All I wanted was the ball: put it on the spot, get it over and done with”. Or Chris Waddle in 1997 “I just wanted it to be over”. These players appear to be suffering from a form of emotional distress, and the natural reaction is to try and get it over with as quickly as possible. Unfortunately, this can mean less attention on the task required.

There are two strategies when it comes to taking penalties. In the keeper-dependent strategy, the kicker varies their shot according to the keeper’s actions, attempting to score in the opposite corner to the one where the keeper has dived. In the keeper-independent strategy, the kicker ignores the keeper, and makes a pre-planned shot. The keeper-dependent strategy is thought to be inferior, because unless the keeper dives early, there’s insufficient time to make the necessary adjustment, and they’re not actually looking at where they intend to shoot.

Yet Kuhn (2008), analysing penalties in top-level German football, found that 70% of all penalties used the keeper-dependent strategy. Why would 7 out of 10 professional footballers use completely the wrong strategy for something that is designed to determine the outcome of the match?

We’re back to stress and anxiety again. I like to think of the effect of anxiety in sport as turning you from a predator into prey. A lion hunting zebra will scan the herd looking for any weaker individuals. When the chase is on, the prey will be closely observed to pick out any deviations in course, and finally the focus will be on the target area for the attack. All the time, the eyes move ahead of the action, picking out relevant visual cues, relaying back visual information to enable the task to be successfully completed.

However, when you‘re prey, you constantly on the lookout for threats. When a threat is perceived, the body usually goes into a set of pre-programmed responses, such as “run” or “play dead”.
Coming back to sport, it means that instead of focusing on the parts of your vision that are required to be effective, the focus is drawn to perceived threats, such as the goalkeeper in a penalty shoot-out.

This change in visual behaviour under stress leads to the ironic effect that player’s intense desire not to miss leads to precisely the behaviour that most likely to cause them to miss – i.e. not looking at the target. This effect has been found in several sports such as basket free shots (Wilson, Vine & Wood 2009) and golf (Binsch et al 2006). When it comes to penalty taking, Bakker et al (2006) found that telling players “not to shoot within reach of the goalkeeper” made them significantly more likely to shoot within reach of the keeper than telling them to “aim as accurately as possible”.

I’ve really only scratched the surface of what’s required to take successful penalties, and I haven’t even started on the best strategies for saving them. Bearing in mind that 22% of the goals scored in the 2010 World Cup in South Africa, there’s no excuse for not preparing your side properly for them.

David Donner

Monday, 6 June 2011

Olympic Countdown - Badminton

This is one sport where I’ve applied for tickets, for two reasons: I used to play regularly, and it was also the subject of my practical work when I took a Sports Vision Diploma about ten years ago.

For that diploma, I looked at the Sussex Under-13 badminton squad, of which my son was a member at the time. I conducted a series of visual tests and compared the results with the coaches’ estimation of the players’ abilities.

For nearly every test there was no correlation between vision and ability. There was one test, however, in which you have to read out some numbers that are close to you, and some that are further away, alternating from one to the other.

Actually, this test showed no correlation with ability either. But it occurred to me that this was a test of speed of vocalisation as well as vision. So I got the kids to read out the numbers from a page, and subtracted this time from the time it took to do the other test. And when I did that, I got a statistically significant correlation with the coaches’ player ratings.

The test is supposed to show the ability to focus clearly on different objects when moving the eyes between them. But it’s actually possible to do the test without moving your eyes, by taking in central and more peripheral information at the same time. Such a skill is clearly important in badminton, where you need to concentrate on the shuttle but be aware of your opponent’s position as well. And indeed this is a required skill in many sports.

One evening when I was playing, a coach was feeding shuttles to a young player, who was returning them with drop shots to the coach who stayed in the same position just the other side of the net. The problem with this is that it’s a form of “blocked” training, which doesn’t take into account the tactical side of the game that’s required in a match. Players can look good in training, but regularly under-perform on match day, or can’t progress their game beyond a certain level.

It would have been much better if the coach, having fed the shuttle from one position, moved to a different place to which the return had to be made. Or he could even have instructed the player to return the shuttle to where he wasn’t, which would have been even more realistic.
I guess the young man won’t be representing the UK next year.

David Donner

Thursday, 28 April 2011

Olympic Countdown - Archery

There are 26 different sports being played at the 2012 Olympics. Some clearly have a greater link with sports vision than others, but few would have a greater reliance on vision than archery. Or so you would think.

When aiming in archery, it’s better to keep both eyes open as this helps balance. It’s harder to balance on one leg, for instance, if you’ve got one eye closed rather than both open. However, this does present a problem: something must be double.

If you point your finger at a distant object and concentrate on that object, you’ll see two fingers, the one on the left being the one that’s aligned with the right eye. And if you focus on your finger, you’ll see two objects, and this time it’s the one on the right that’s aligned with the right eye.

The other problem is that if you focus on your finger, the object will be slightly out of focus, and vice versa. In archery, the “finger” is a sight on the front of the bow. It seems to promote accuracy by focusing on the target, and having a slightly out of focus bow sight. You also need to make sure that it’s the left hand sight that you’re aligning, assuming that you’re using the bow right-handed.

I said that you’d think that excellent vision would be essential for any level of archery, but in fact some partially sighted or even blind archers can be remarkably accurate. How do they achieve this?

Well, they have two aids. One is a foot locator, which is a wooden frame, and against which they place their feet. It is built to the archer’s stance, which ensures that their feet are in exactly the same position each time. The other is a tactile sight, which consists of a fully-adjustable spring-loaded bar which touches some part of the archer’s hand when the bow is fully drawn. They also have a “spotter” who tells the archer the result of the shot, and helps with adjustments of the tactile sight.

This makes me wonder how care fully sighted archers take to ensure that their body position is exactly the same each time. At an elite level, a side-on video camera could relay picture onto a screen, then you simply subtract one image from the previous one to see if there’s been any change in position. I bet it would be a pretty good guide to the accuracy of the shooting.

Visually impaired archery is not currently an Olympic sport, but it is hoped that it will be by the 2016 Games.

David Donner

Tuesday, 29 March 2011

Training To Win!

A coach was recently telling me how his Colts side prepared for a big match. Both sides were unbeaten all season, but the other team were quite strong favourites.

A couple of days before the match his colleagues advised him that some light training would be best, but he insisted on a full contact session. His team went on to win the match 10 -9. The opposition had a long period of play just a few metres from the line, but time and time again the tackles were made to prevent them crossing for a try.

Obviously a balance needs to be struck. You need to give the players a chance to recover from a previous match, and you don’t want them exhausted because they’ve over-trained. But as a general principle, practice should be in some respects at least as difficult, if not harder, than playing a match.

So if you’re wondering why England failed to win the Grand Slam in Dublin, and were completely outplayed and outfought by Ireland, then maybe you need to know just one thing: England had only light training all week.

David Donner

Thursday, 3 March 2011

Rugby Passing 2

Of course backs are also perfectly capable of dropping the ball. One of the most common causes is simply taking their eyes of the ball, being distracted by the opponent advancing towards them, or looking at the inviting try line ahead, for instance. This is particularly likely to happen if your passing drills are unopposed.
It could be that the weather is particularly bad on the day of the match and the ball is slippery. But why not practice this by making the ball deliberately wet or greasy? As well as preparing the players for quite a likely eventuality, it would also make them watch the ball into the hands more carefully.
There is another category of errors which comes from when the ball shouldn’t have been passed at all, because there was no one in position to take it. One of the things that set the top players apart is their decision making. They take the opportunities that come their way, but they don’t make rash decisions if the opportunity isn’t there.
A simple variation to touch rugby could introduce the concept of decision making from a young age. The attacking side forfeit the ball if they’re touched in possession of knock on as usual. But they would also have another option. If a player shouts “tackle” before they’re touched, they must stand still, but are allowed to pass the ball when a team-mate becomes available. The coach would decide how many times this “tackle” option would be allowed before the usual rules are back in play.
The key to making good decisions is using ones vision to analyse the situation as much in advance as possible. The players should therefore be told that they should expect that the ball is always going to come to them, and to think about what they’re going to do before the pass to them is made. But they also need to keep monitoring the position of their own and opposition players so they can change their mind at the last moment if necessary.

David Donner

Passing In Rugby

The standard of passing in the Six Nations so far this season has been rather variable, from excellent to the frankly ridiculous. Sometimes the guy with the ball is so desperate to keep the ball alive, either to stop it going out of play and conceding a line out, or because having beaten two or three people he’s got carried away, that a totally inappropriate pass is given, which the receiver has no chance of catching, and may even be picked off by the opposition.
Sometimes, however, a perfectly acceptable pass is made, and then dropped. If it’s a forward who’s dropped the ball, there tends to be a collective “If only that had gone to a back” reaction. But how much time is spent on improving the handling skills of forwards?
The process of catching the ball starts long before the hands try to make contact with the ball. The fly half could probably recognise the type of pass (e.g. spin, pop pass or loop pass) from the scrum half well before the ball is actually released. But a forward is less likely to be less able to do this.
So one could start by getting the scrum half to demonstrate some different passes to the forwards who would be told to watch how the scrum half shapes to pass the ball, to watch the ball into the hands, and to pay particular attention to the feel of the ball in the hands when it’s caught. This is then repeated while taking the ball on the run. Some deliberately poor passes – too high or low – can be added as passes won’t always be perfect in a match.
The final stage would be to convert this drill into a more realistic match practice. For instance, three forwards have to score a try past two defenders. The move begins when the scrum half makes one of the previously demonstrated passes to one of the forwards of his choice as they’re running forward. The three then have to use passing and movement to ensure their numerical supremacy counts.

David Donner

Friday, 4 February 2011

Peripheral Illusion

Have a look at this website:

It’s a wonderful example of the differences between the central and peripheral parts of our vision. The central part is especially sensitive to detail and colour, whilst the periphery is more sensitive to movement and faint light.

The difference reflects the different light-receptor cells that are present in the retina – cones in the centre and rods more peripherally. It’s why in the days of navigating by starlight, sailors were told to look for faint stars out of the corner of their eye.

Most of our waking time is spent using our central vision, such as looking at a computer screen or TV, reading or talking one-to-one. If there’s something peripherally of interest we tend to turn our head to look at it.

In many sporting situations, however, it’s necessary to be able to assimilate a lot of information from the periphery, such as the movement of team mates, even if the main focus is on the opponent directly in front.

This can be learnt, with the right kind of coaching.

David Donner

Friday, 14 January 2011

The One Eyed Referee

All sports officials are meant to be objective and neutral in their decision making. In theory, therefore, two officials of the same standard should make more or less the same decisions in the same situations. In practice, however, decisions are often made in the context of personal style, the match situation, previous experiences, and (mostly) subconscious biases.

Some sports actually incorporate subjectivity into their laws. In rugby, for instance, the referee is the sole judge of whether or not advantage has been gained. In cricket, the umpire has to decide whether or not short-pitched bowling is unfairly intimidating, taking into account the batsman’s ability. Nevill et al (2002) showed 47 football situations on video to a set of referees. None of them received a unanimous verdict from the refs.

Personal style is undoubtedly a major factor in many decisions. For instance, in rugby, some referees may want to establish their authority early, whilst others may wish to allow the game to flow without being seen to be overly fussy. The referee might be influenced by previous incidents in the game, or even from a previous match between the same opponents. There may also be some benefit given to a side that’s losing heavily.

Trudel, Dionne and Bernard (1999), as well as Gilbert, Trudel & Bloom (1995), in assessing ice hockey penalties, concluded that referees, compared with players and coaches, attached greater importance to the context in which the infraction had occurred. Gilbert et al revealed that both the score and the time remaining in the game influenced decisions about whether or not to award penalties.

Diane Ste-Marie of the University of Ottawa has done a lot of research, especially in gymnastics, into how judgement can be affected by previous experience. She found that if judges were shown a performance on video with an error, they were more likely to see non-existent errors in the second tape. The effect lasted even if the second tape wasn’t seen until a week after the first one, so could affect an athlete performing in several rounds, or even if they’ve been seen in a warm-up. A similar effect has been found in figure skating.

Other assumptions made by officials can be just as erroneous. Damisch et al (2006) showed experienced judges two routines on the vault. If they were told that the two athletes belonged to the same national team, the two routines received similar scores. But when they were believed to be from different teams, the scores were less similar.

There’s also been concern that some judges might be influenced by the opinions of other judges, in so-called “conformity bias”. Boen et al (2008) found that gymnastics judges’ scores were more even when they had feedback about each other’s scores. The effect continued even after feedback was no longer being provided, suggesting that once the judges felt reassured that they had given a “correct” response, they were no longer worried about standing out from the crowd.

The decisions of referees and umpires can sometimes be influenced by prior knowledge of the teams or players (Plessner & Haar 2006). It has been shown that the previous reputation of players can influence the decisions of referees in basketball (Lehman & Reifman 1987), in baseball (Rainey et al 1989). In football, Jones et al (2002) found that players with an aggressive reputation were penalised more severely than players with no such reputation.

A major benefit for a football team playing at home comes from crowd support. It seems that part of this benefit is from the effect that it has on the referee. Dawson et al (2007) found that the home side was more likely to get favourable decisions in terms of fouls and red cards. The amount of extra time allowed is higher when the home team is behind than when it is in front (Dohman 2008, Garicano et al 2005, Sutter & Kocher 2004).

Studies suggest that this home team bias is because of the influence of the home crowd (Bokyo et al 2007, Page & Page 2009), although it seems to have more of an effect of some referees than on others. With some referees, the amount of home bias is directly proportional to the size of the crowd, whereas for others the effect is constant, regardless of crowd size (Page & Page 2009). If there’s a running track around the pitch, the influence of the crowd on referees’ decisions seems to diminish (Buraimo et al 2008).

It could be that referees are simply alerted to the presence of a foul by crowd noise. Nevill et al (2002) found that referees looking at video footage (Liverpool v Leicester City) were much less likely to give advantage to the home team when the sound was turned off compared with when it was on.

Favouring teams or individuals of the same nationality as the official has been found in numerous sports, especially those that are judged subjectively. Clear national favouritism has been found in figure skating (Seltzer & Glass 1991, Whissell et al 1993, Campbell & Galbraith 1996), gymnastics (Ansorge & Scheer 1998, Ste-Marie 1996), ski jumping (Zitzewitz 2006), rhythmic gymnastics (Popovic 2000), Thai kick-boxing (Myers et al 2006) and synchronised diving (Emerson et al 2009). In all these sports, referees have been shown systematically to be giving advantage to competitors from their own countries, and the effect is significant, because the result often determined by the referee’s decision.

Even in sports where the result is not so closely tied to the decision of the referee, there has still been evidence of a national or local bias. Mohr & Larsen (1998) found that referees in Australian football were more likely to favour teams from their own states in matches against teams from another state.

At a national level, football, rugby and cricket usually have neutral officials. Page & Page (2010) looked at two cases where referees were allowed to officiate in inter-club matches where the team from their nation played a team from another nation. These were in rugby league the European Super League 2006 – 9 (mostly British teams with one French team), and in rugby union the Super 14 2009 (5 South African, 5 New Zealand and 4 Australian teams).

In Super 14, a referee with the same nationality of a team increased the score of that team by on average 5 points relative to when there was a neutral referee. The home team won 71% of its matches when the referee was of its own nationality, compared with 50% when the referee was of the nationality of the away team.

In Super League, the French team received on average 9 points more in a match when the referee was not English. They won 67% of their matches when the referee was Australian or French, compared with only 41% when the referee was English. The effect varied according to whether or not the match was televised. When the referee was English, the French team was much more successful when the match was on TV (59%) than when it wasn’t (30%).

The effect of favouritism was most pronounced when the decisions were critical. When there was an English referee, the French team received twice as many cards as the English team, but when the referee wasn’t English they received roughly the same number.

Page & Page also studied the rugby league Championship, which had one French team and mostly English referees. They looked at decisions involving whether or not the ball had been grounded in scoring a try. French teams had a lower proportion of positive decisions (79% against 93%).
Favouritism was also particularly strong when the score was close, with English and French referees favouring the side of their own nationality when it mattered most. In the Championship, when the difference between the sides was 4 points or less, the French team had only a 59% chance of getting a try validated, compared with 82% for the English team.

Because so many of the decisions made by officials are a matter of opinion, such as LBW decisions in cricket, the individual can justify to themselves that they made the correct decision according to the laws of the game, and will genuinely not be aware of their own bias. There are many factors that go into making a split-second decision, including the attitude of the players, the crowd or spectators, the personality of the official, and even their mind-set on the day.

It’s important therefore that during their training, officials are made aware of these factors, and are given as much practice (e.g. videos with crowd noise) and feedback as possible to enable them to improve their consistency. Because one thing seems clear: in many sports, officials’ decisions have a large effect on the result of the game.

David Donner

Are You Blind Ref?

Quite a bit of research has been done on the visual requirements of different sports, but very little on the requirements for sports officials.

There are, of course, several different kinds of officials. For simplicity, I’ll put them in four main groups.

Recorders include cricket scorers, and those who measure distances and times in athletics. Line judges would include line umpires in tennis, but would also include some who can occasionally intervene in play, such as touch judges in rugby. Referees and umpires are an integral part of the game, often making an enormous number of decisions, as in cricket, rugby and football. Finally, judges give a rating to a performance, but are external to it, for instance in gymnastics, diving and figure skating.

Some officials will cut across these boundaries, such as tennis umpires. There are also other officials who are further removed from the performance, such as tournament referees, 3rd and 4th officials.

I'm going to be concentrating on those officials who have to make decisions, but even recorders rely on vision. Cricket scorers in particular have quite high visual demands as they are a long way from the action. Recognising batsmen under helmets from outside the boundary can be difficult, and may require other features to be found, such as the markings on the bats. Scorers also need to be careful that they are ready to acknowledge any signal from the umpire, and aren’t looking down at the scorebook at that moment.

All officials, therefore, should have regular eye examinations to ensure that their judgments aren’t being distorted through any defects in their vision. This should usually include an assessment of their field of vision, as significant defects could result in some of the action being missed completely.

Assuming that the official has a good standard of vision, if necessary corrected with either spectacles or contact lenses as appropriate, we can look at how vision is an integral part of the decision making process for sports officials.

We've already seen how perception can affect line decisions in tennis (see “You cannot be serious” blog). This same effect could also cause assistant referees to flag a player offside who isn’t, and an umpire give a narrow run out decision in favour of the batsman.

Tennis line umpires are in a more or less fixed position, but the positioning of officials can be a crucial factor in their decisions. Oudejans et al (2000) proposed that many incorrect offside decisions in football were as a result of the referee’s assistant being behind, rather than level with, the last defender. The Dutch researchers correctly predicted that this would lead to more wrong calls of offside than missed calls of actual offside. But presumably, this would depend on whether the attacker was on the far side of the defender or near side, as viewed by the official. So it could be that they were actually confirming Whitney’s theory of perceptual delay (described in “You cannot be serious”). Nevertheless, it must be the case that poor positioning would cause errors due to simple parallax, even if they don’t necessarily favour the defender.

One of the things that can help with positioning is anticipation. For instance, if a rugby referee can anticipate a likely drop goal attempt, they’re more likely to be able to get in position to be able to tell whether or not the kick is successful.

Ste-Marie (1998) expert gymnastics judges showed better anticipation than novice judges. All judges were more accurate when they had seen the same performance earlier. If there was some minor difference in the two performances (e.g. bent knees versus straight knees) they were less accurate, and if the second performance had a completely different element to the first, this produced the least accurate judgements.

So whilst correct anticipation can lead to improved judging, incorrect anticipation can lead to inaccurate (though rapid) judgements. Judges therefore need to be able to recognise when a new element has occurred, and take the necessary time to re-evaluate it. They also need to keep an open mind at all times. Ste-Marie found that if judges were shown a move with an error, they were more likely to see non-existent errors when the move was repeated a second time.

A difference that is often seen between experts and novices in sport is how they make better use of visual information in decision making. Expert tennis players, for instance, will focus on certain parts of their opponent’s body when determining the direction of their shot. Is there any evidence for officials doing this?

Well, there is some. In gymnastics, for instance, Bard et al (1980) found that expert judges watched different areas of the body than did novice judges. Sed (2008) found a similar result in basketball. When asked about their thoughts when watching a DVD of a match, expert basketball officials focused on specific areas of the court, whereas novice officials tended to watch the ball. This enabled the experts to anticipate better the movements of the players.

Smith & Millslagle (2008) used head-mounted cameras to assess the gaze fixation of elite and novice umpires in softball. They found that when the pitcher released the ball, the elite umpires’ gaze location was 100% on the ball, whereas the novices’ gaze location was only 55% on the ball.

Considering officials that are an official part of the game, such as rugby and football referees, there are a large number of decisions that need to be made during a game. A study of football referees during the EURO 2000 championships found that they made, on average, 137 observable decisions. That didn’t include all the unobservable decisions (approximately 60), such as deciding not to blow the whistle. Most of these decisions have to be made within time constraints. Australian Football League referees were found to have less than a second in which to make their decisions (McLennan & Omodei, 1996).

Cricket umpires generally have more time to make their decisions, but one exception is in determining whether the bowler has no-balled or not. The umpire has to decide very quickly whether or not the bowler’s feet are legally placed before switching gaze to pick up the flight of the ball in anticipation of a possible LBW decision.

The relevant Law begins “In the delivery stride, the front must land……” When I was training to become a qualified umpire, we had to learn this off by heart, and if our answers didn’t have the words “in the delivery stride” we would lose marks. But when you’re umpiring you don’t have time to think about the words, you have to instantly recognise whether the feet are in an allowed position or not. The same goes for a rugby referee when judging whether a tackle is legal or not.

The training of umpires has now improved, and much time is spent demonstrating feet positions, for example. The idea is that these images are stored in the visual memory, providing an instant comparison to be used on the field of play.

If we are to improve at something, we need some kind of feedback to judge whether or not we are actually improving. One of the few studies on the use of feedback for sports officials was by Jendrusch et al (2002) for tennis line judges. Electronic devices were used to assess where the ball landed. Those line judges who received accurate feedback about their decisions showed marked improvements compared with those who didn’t. They showed no general improvement in perceptual skills, but simply learned what to look at when making decisions. A similar system could be used to improve the accuracy of cricket umpire’s LBW decisions using Hawk-Eye.

If we want to improve the decision making of referees and umpires, it would be helpful to know whether this can only be done on the field of play, or whether video training can also be used. One attempt to do this has been by Brand et al (2009) with the SET - Schiedsrichter-Entscheidngs-Training (Referees Decision-making Training). Videos from a variety of competitions are shown, including the German Bundesliga and the UEFA Champions League. Each video is stopped after a crucial incident, usually a contact between two players, and the participant clicks with a mouse to indicate their decision. This system has been cleverly designed to enable several parameters to be changed, such as how much time is allowed to make decisions, and whether feedback about the correctness of the decision is given immediately or delayed. Extra information can also be inserted, such as shirt colour and crowd noise, to explore the extent to which irrelevant information is used (See “Is the ref biased?”).

They've found that it’s better to give immediate, rather than delayed, feedback on the correctness of decisions. This resulted in the most effective increases in decision accuracy.

One limitation with the SET is that the video clips were taken from external pitch side cameras, so do not give the referee’s actual view. This was also a limitation of a Canadian study in which video clips were shown to rugby referees (MacMahon 1999). The experienced referees wanted to know more information than was provided, and often felt the videos gave them a poor view. One answer would be to fit a referee with a head-mounted camera. Another specific problem was that the referees wanted to see whether there was going to be advantage or not, despite the fact that they were told to ignore the question of advantage.

Another use of video has been in point sparring, which is a scoring system used in some martial arts. The determination of whether or not a point has been scored can be a subjective decision by the referee. Krueger (2008) found, unsurprisingly, that first-time referees were significantly less accurate in their scoring compared with more experienced ones. More surprising, perhaps, was the finding that accuracy was generally less when the standards were higher and the two fighters were more evenly matched. This meant that in the finals, when, at least in theory, the two best fighters met, the accuracy of decisions was lowest.

They also found that a referee with 20 years’ experience was generally no more accurate than a referee with only 2 years’ experience. This suggests that experience without feedback can lead to a plateau effect. Virtually all the referees showed systematic errors that could be easily corrected. One referee occasionally awarded a point to obviously the wrong person, apparently confusing which fighter was which. Another was generally accurate, but would make several errors in a short period, suggesting lapses in concentration.

Just as ProBatter has been used to give England’s batsmen a realistic idea of what it’s like facing Test bowlers, virtual technology should in time be able to give officials experience in an environment where mistakes aren’t too costly. Important factors such as crowd noise could easily be incorporated.

In the meantime, I’m always surprised how little officials are used in players’ practice sessions. Not only would it give novices a chance to develop their experience, but established officials could use it to “get their eye in” before the start of the season.

This would also benefit the players. How many bowlers overstep in the nets? Would there be so many offences at the break down if there were referees at practice games?

A novel way of giving trainee officials relevant experience and feedback has been tried in the Australian Football League. First year umpires are given green shirts, and are monitored by an experienced referee during a game. They may be asked to concentrate on just one call, and may stay on the field for a limited amount of time, giving them a chance to reflect. In rugby union, for instance, a similar system might have trainees concentrating on the straightness of the throw or the spacing between players at the line out.

I’m sure a lot could be learned from time on the pitch with an experienced referee, learning how to look in the right places for likely offences.

David Donner

Tuesday, 4 January 2011

Look Black In Anger!

In my blog about wearing different colours in sport, I talked about the advantage of wearing red in tae kwon do, where it appeared to give the perception to judges that the wearer was more aggressive. The suggestion that wearing red was advantageous in football was much less conclusive.

One colour I didn’t mention was black. Frank & Gilovic (1988) found that wearing black in American Football and ice hockey led to a perception of increased aggression, but in this case it was a disadvantage because it led to more penalties against those teams.

They analysed five NHL teams with 50% or more black in the uniforms, and five NHL teams. All of the dark-colour teams were near the top of the group in terms of penalties awarded against them for aggression. Two ice hockey teams that switched to black uniforms during the season saw an increase in penalties.

When two identical American Football games were shown with the uniform colours reversed in the different versions, those watching felt that the black-uniformed team was more likely to be penalised. Turning off the colour on the video eliminated the effect.

There may even be an effect from just wearing black. College students chose more aggressive sports from a list for further competition when they wore black.

It has to be said that the New Zealand All Blacks don’t seem to have suffered too much from this effect. On the other hand, might it be part of the reason why football referees get so much stick?

David Donner

Stoop to Conquer!

It’s been remarked by football commentators that Peter Crouch seems to be penalised a lot, especially by Continental referees. It seems that he may not be alone, because there would indeed appear to be a bias against tall footballers.

Quaquebake and Giessner (2010) analysed more than 100,000 fouls from the UEFA Champions League, German Bundesliga and FIFA World Cups. They found that taller people were more often held accountable for fouls than shorter ones – even when no fouls were committed.

It’s not clear why this should be, but it seems that in close decisions, the player’s height is used as an additional piece of information by the referee. It could be that very tall players are seen as a bit uncoordinated, or as overly aggressive. Either way, it seems to be another of those assumptions that are made about people which, even if they may have a grain of truth in them, can also be grossly unfair to the individual concerned.

Much more on referee bias later.

David Donner