Thursday, 18 April 2013

The return of ...It Must Be Love!

“The blogs are great” says Dan the Man, “but you need something to brighten them up occasionally: any more tennis stories?” Who does he think I am? Jeremy Clarkson? I don’t race across Africa or interview celebrities. I play tennis with some other blokes, and if we were supermarket products we’d be labelled “Best before 1990”; or in some cases “before 1970”; or in others “Not applicable”. We seem to have picked up a few injuries recently. It started when I was playing with Jonathan the slice against Barry the Beard and the Reverend Ian. They had played quite a few drop shots in front of JtS which he had got nowhere near, so when they played another one cross-court I decided to go for it. Unfortunately, JtS decided to go for it as well. I actually thought it was quite an achievement to deliver a body check on my partner that a NHL ice hockey player would have been proud of, and which put him out of action for three weeks, whilst at the same time completing a backhand down the line for an outright winner. BtB, being Barry, claimed he was “too busy watching you to kiss and cuddle to attempt to go for the ball”. Fortunately, I remembered an earlier moment when BtB’s momentum when going for a shot on the baseline had sent him careering off towards the next court where he met Roger the Backpacker running in the opposite direction. “You can talk” I said. “At least I didn't run off the court to do it. You were like a schoolgirl who’s just seen Justin Bieber”. Unfortunately I’d forgotten that Barry’s knowledge of 21st Century cultural references couldn't exactly be described as encyclopedic. “Who’s Justin Bieber?” I've also heard that Barry the Beard has had a nasty injury when he ran off the side of the court into a brick wall the other side of the netting. Apparently the netting was too close anyway and he’s considering legal action. Our group is known as “The Doctors” because there were originally two doctors in it, although we now only have a retired anesthetist. We do have two retired solicitors, so when someone’s lying on the ground injured there’s invariably a call of “Let me through, I’m an injury compensation lawyer”. And then last week I looked across to the next court after hearing some kind of commotion. Roger the Backpacker was holding his nose in some discomfort. For some reason, the thought occurred to me that his partner, The Reverend Ian, had completely lost it and punched RtB in the face. I immediately dismissed the thought and assumed that the two had collided accidentally. It turned out, however, that Roger had contrived to hit himself with his own racket. It was one of those unifying moments when, as the blood started to seep from RtB’s nose, the rest of us were clearly thinking the same thing: “If only we’d had a video camera to record that”. Because it is a truth, universally acknowledged, that there are few things more enjoyable than watching someone else carry out a completely self-inflicted injury. It was as if Richard the Poke had carried out his trademark “stroke” (for want of a better word) in reverse. But that wouldn't have carried sufficient force even to reach the nose, let alone break the skin. No, this was made with the full swing of the racket, which makes the achievement of following through right in the middle of your own face all the more remarkable. So I’m going to start wearing one of those cameras that are used to determine what elite sportsmen are looking at. Of course I shall say it’s in the name of research, but I will actually be hoping that history repeats itself and I can sell the video. All those channels that just endlessly repeat old shows could replace them with an endless loop of RtB attempting to rearrange his own conk. Not only would viewing figures soar, but the World Database of Happiness (believe me – there really is such a thing) would show Britain soaring up the happiness league table. Someone should tell David Cameron. David Donner

The A-Z of Sports Vision - Knowledge

Coaches are expected to give their athletes some feedback about their performance, and this can mean the athletes can gain different types of knowledge. Knowledge of results tells athletes how they have performed in relation to the goal they were trying to achieve, whereas knowledge of performance tells them about the quality of their performance, regardless of the outcome. Knowledge of results includes how far a long jumper has jumped, or the score of an archery shooter. Of course, there are many times when the result is obvious to the athlete, such as whether or not a shot has resulted in a goal or been saved. There are risks involved, however. For instance, a tennis player can see if their serve has landed in or out, and may be tempted to play safe and go for accuracy which may limit the development of their serve. Novice tennis players will know that they are hitting some shots harder than others, but are unlikely to have precise information about how fast the ball is travelling. Davies (1989) used an artificial method of giving this feedback so that the speed of the serve could be increased. The player served at a wall the same distance away that the net would be. Two lines were marked on the wall – one at the height of the net and another some feet higher, above which it had been assessed that the service would be “long”. The knowledge of results came in the form of the distance of the rebound from the wall. The player’s service speed rose rapidly, and the player was able to select for himself the most appropriate service technique. This is essential; otherwise when knowledge of result is withdrawn the performance will decline to its previous level since nothing will have been learned. Knowledge of performance might include the coach telling the player they should have passed the ball when they took a shot, or a technical comment about a bowler’s action. Video can be an effective way of giving athletes knowledge of their performance. I recently videoed some scrum halves passing the ball, and it was immediately apparent that they tended to kick their back leg out as they released the ball. This is clearly an attempt by the subconscious brain to retain balance, but it suggests that they are not as balanced as they should be in the first place. The trick now will be to get them to be more balanced without having to think consciously about their feet placement, as such an internal focus is likely to affect their performance adversely. I’d like to give them an image that would encapsulate the whole movement. By the time we get to “V for video”, I should know how successful I've been. David Donner

Tuesday, 9 April 2013

The A-Z of Sports Vision - Jumping the Gun

In international sprint events, such as the 100 metres, a false start is called if an athlete’s foot increases the force on their starting block within 100 milliseconds of the gun. The IAAF decided on this threshold in the belief that humans cannot react to a sound in less than 100ms. Is this right? Komi, Ishikawa & Salmi (2009) found that there was quite a bit of variation in reaction times, and that the values in some cases were even below 80ms. They therefore recommended to the IAAF that the value should be reduced to 80 or 85ms. They also suggested that high speed cameras should be used to detect any first movement before the set minimum reaction time, rather than pressure on the blocks. Brown, Kenwell, Maraj & Collins (2008) reviewed reaction times for the 2004 Olympics in Athens. They found that runners in Lane 1 had an average reaction time of 160ms, whereas those in Lane 2 took 171ms. The slowest lane, for some reason, was Lane 7 (rather than the expected Lane 8) with 185ms. When experiments were carried out on athletes and non-athletes, they found that non-athletes had faster reaction times when the sound was louder. Assessment of their blinks suggested that being startled produced faster reaction times. Athletes, it seemed, were able to produce their fastest reactions without being startled. During their experiments, the researchers noted that 21% of participants recorded reaction times faster than 100ms, although subjects only had to move an arm in response, rather than their whole body. Nevertheless, it’s interesting that Linford Christie was disqualified in the 1996 Olympic final with a reaction time of 86ms, and was convinced that he had not jumped the gun. One other thing: Lipps, Galecki & Ashton-Miller analysed reaction times of male and female sprinters at the 2008 Beijing Olympics. They found that men and women could react in as little as 109ms and 121ms respectively. However, they believe that this difference is an artefact caused by the fact that the rule of how much extra force is needed to put on the blocks to register a start time is the same for both men and women. Taking into account the less muscle strength of the women compared to the men, the force requirement should be reduced by about 22%. Effectively, they claim, this allows women to false start by up to 21ms without penalty. If they had a visual system of starting, such as a light flashing on, and a visual system to detect early movement, perhaps it would all be fairer. David Donner

Eye Colour and Trustworthiness

Does the colour of your eyes indicate how trustworthy you are? Research by Kleisner et al (2013) appears to suggest that it does. Some aspects of behaviour and eye colour have been researched previously. For instance, Rosenberg & Kagan (1989) found that blue-eyed infants were more inhibited, shy and timid than brown-eyed infants. Coplan et al (1998) found that boys with blue eyes were socially warier than boys with brown eyes, although no such differences were found between blue- and brown-eyed girls. In the latest experiment, 238 participants were shown photographs of 40 males and 40 females, and rated them for trustworthiness on a scale of one to ten. In order to check if eye colour was really the relevant factor, the irises were then re-coloured using Photoshop. These re-coloured photos were then assessed for trustworthiness by a second group of 106 participants. They found that brown-eyed faces were perceived as more trustworthy than the blue-eyed ones. For male faces, the eye colour of those rating the photos had no effect. But for female faces, those with blue eyes received lower ratings from those with brown eyes than with blue eyes. However, all those doing the rating, irrespective of their own eye colour, perceived brown-eyed faces as more trustworthy than blue-eyed ones. But when the eye colours were digitally changed, there was no change in perceived trustworthiness, showing that it wasn’t actually eye colour that was significant. So what was going on? It turns out that men with a larger mouth, a broader chin, a bigger nose and more prominent eyebrows positioned closer to each other were rated more trustworthy. And brown-eyed men are more likely to have these characteristics. There was a similar but insignificant effect for women, possibly because of less variation in female face shape. As the Eagles put it, “You can’t hide your lyin’ eyes”. David Donner

The A-Z of Sports Vision - Inattentional Blindness

Some years ago I was driving along and in front of me was a van waiting to turn right into a side road. The driver appeared to be waiting for a motorcyclist coming in the opposite direction before turning. However, to my horror, he started to turn at exactly the moment the motorcyclist drew level with him. It was almost as if the van driver had been waiting for the motorcyclist before turning into him. I’m sure that wasn’t the case, but this was actually an example of “inattentional blindness”, and is a common cause of accidents between cars and motorcycles. Fortunately, in this case the motorcyclist wasn’t too badly injured. The term inattentional blindness refers to the failure to detect an unexpected object or event if attention is diverted to another task or object, even if it is right in front of the observer (Furley, Memmert & Heller, 2010). One of the most dramatic examples of inattentional blindness was demonstrated by Simons & Chabris, (1999). In a series of experiments, observers watched a video of two teams playing basketball. One team wore white shirts, the other black, and the observers had to count the number of passes made by either the white team or the black team. Partway through this task, either a woman with an umbrella or a person in a gorilla costume unexpectedly walked through the centre of the action for about five seconds before exiting the display. The observers were then asked if they had seen an unexpected object. 35% of observers failed to notice the woman with the umbrella, and 56% failed to notice the gorilla. In sport, there’s a balance between being focused on what you’re doing, and being so intensely focused on one area that you miss important information elsewhere. Because players can’t absorb all the information that might be presented to them on a sports field, coaches often guide them towards which cues to take notice of and which to ignore. The danger, however, is that this can make them blinkered and adversely affect their decision-making. Interestingly, it’s been found that expert athletes seem to prefer to pay proportionally less attention to highly likely events and more attention to less likely events (see Memmert, 2009 for an overview). In theory, this should mean that experienced athletes should be less susceptible to inattentional blindness. When Furley, Memmert & Heller (2010) studied expert basketball players, they found the phenomenon was still strong, although they were indeed not as susceptible as novice players. This indicates that predetermined plays, such as are often seen in American football, may not be the most advantageous. A less rigid approach, with fewer instructions, might actually be beneficial. Inattentional blindness can be an especially big problem for officials. In football, for instance, the referee might be distracted by some shirt-tugging, and not notice a handball, or even the ball crossing the goal line. I look forward to the day when the chant goes round the ground “You must be inattentionally blind, ref!” David Donner