Friday 23 April 2010

The Principles of Sports Vision

If you thought sports vision was all about eyesight or eye exercises, think again. Sports vision, like sport, is all about the brain.

World Cup, Mexico 1970. The ball is at the feet of the world’s greatest player. As the Italian defence is transfixed, Pelé rolls the ball across where Carlos Alberto, without breaking stride, smashes it into the bottom left hand corner of the net.

England v Wales, Twickenham 2010. Matthew Tait is one-on-one with Shane Willliams. He checks inside, then out. As he’s tackled, he flips the ball backwards giving James Haskell an unopposed run in to the try line.

Most sport consists of making a movement in response to what you see. For instance, you see a ball and you hit it, or kick it, or catch it. If you have a weakness in your sight, it makes it more difficult to do this. Such problems can usually be solved by wearing contact lenses, or sometimes with exercises. But elite sportsmen aren’t usually able to read much further down the chart than average. Nor are they able to move their arms or legs around in some amazing way that the rest of us can’t. They are, however, better at coordinating their vision with their actions, and that’s done by the subconscious brain.

The images of what we see that focused on the retinas of our eyes are upside down, back to front, and out of alignment .These images are transferred through the optic nerves to the occipital cortex of the brain. This is where we actually see things. By the time the images have been processed we see a three-dimensional world in which light information has been transferred into objects we can recognise. Our brain also informs us where we are in relation to those objects, the speed and direction of their movement, and organises our body to make any necessary reactions.

The passes that Pelé and Tait made weren’t technically that difficult. Nor did they require exceptional eyesight. But they were made because those players were able to assess their visual information to the maximum advantage of their team over the opposition. And that’s a skill you can only learn through relevant practice. Unfortunately, much traditional coaching doesn’t teach this skill, and can even hinder the process of learning it.

Experts start learning these skills from an early age using either deliberate play or deliberate practice, or both.

Deliberate practice is designed to improve performance, and is especially important in individual sports like tennis. Deliberate play consists of unstructured activities such as playing in the street, or in the park. This encourages fun and improvisation, rather than pure repetition. The best team players have invariably spent a large amount of time on unstructured practice in their childhood.

It’s often said that 10,000 hours of deliberate practice is required to become an expert. In sport, however, Australian research has shown that this figure can be reduced to around 4,000 hours for those who play a range of sports in their formative years. One netball international had only 600 hours of netball-specific practice before being selected for the Australia team. She had, however, participated in 14 other sports as a junior.

Researchers have attached cameras to sportsmen to see if there are differences between experts and lesser players in terms of what they look at when playing sport. Across a range of sports, they’ve found that there are significant differences. For instance, basketball players fixate their vision on a particular part of the hoop when taking free shots. Golfers fixate a particular part of the ball and the hole, as well as the break point if there’s some borrow on the putt. And they hold these gazes for longer than lesser players. Canadian researcher Joan Vickers has termed this “The Quiet Eye”.

Expert chess players can look at a game on progress for just 5 to 10 seconds and then accurately recall the exact location of 90% of the pieces (compared with 50% for the less skilled). They seem to be able to “chunk” the individual pieces into patterns. Expert team sportsmen are also able to visualise the position and movement of players into chunks, so that they are able to recognise patterns of play. They also concentrate their vision on areas or objects that are the most important for decision making. Lesser players don’t see the most appropriate course of action, tending to concentrate purely on what’s in front of them.

Traditional coaching involves breaking down complex skills into specific components, with repetitive practice in which the performer tries to do exactly the same thing every time. High levels of technical guidance are provided by the coach. This type of coaching is very appealing because the athletes feel they are improving rapidly.

However, evidence from a number of sports such as golf, baseball and football suggests that long term ability is greater when the skills are learned as a whole, in the context of what actually happens in a game, with more random practice where different decisions have to be made each time. Skills learned in this way, with more opportunity for self-learning, are also less likely to fail under stress, such as performing in front of an audience.

For more information on Sports Vision visit http://www.donneroptometrists.co.uk/sports-vision.htm


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