The A - Z of Sports Vision - Reaction Times

Research into reaction times goes back more than a hundred years. In 1911 Ladd & Woodworth produced average reaction times for visual, auditory and kinaesthetic (touch) stimuli as 189.5ms, 146ms and 150ms respectively. Since then, other researchers have found similar figures, although improved technology has shown reaction times for kinaesthetic stimuli to be the quickest, at between 120 and 140ms (Vickers 2007). You can actually break reaction times down into different phases. Firstly, the stimulus has to be recognised and an appropriate response prepared. Then there’s a phase where the muscles begin to contract (as measured by electromyography – EMG) but there’s no movement. Finally there’s a phase where the movement response can be observed. Although the average auditory response time is 140-160ms, the threshold for Olympic sprints is lower because reaction time can be decreased with training (Carlton 1981). When Linford Christie was disqualified (see J is for jumping the gun) the threshold was 100ms, but it’s since been raised to 120ms. A group led by Joan Vickers looked at the reaction times of baseball player Mark McGwire. In his career McGwire averaged a home run every 10.61 at bats, the best at bats home run ratio in baseball history (Babe Ruth is second). They looked at videos of his record-breaking 1997-98 season, measuring his reaction time (the time between the release of the ball from the pitcher and the movement of the bat towards the ball) and his movement time (the time between the first forward bat movement and contact with the ball). They found that McGwire waited longer before moving his bat than other great players, and swung his bat faster than any other player in history. This fits in with research by Bahill & LaRitz (1984) who found that college players tracked the ball until it was around 2.75 metres from the plate while Major League players kept up with the ball until it was almost 1.5 metres form the plate. McGwire’s performances don’t appear to have been because of exceptional vision – he actually had poor acuity in one eye and wore contact lenses when playing. This suggests that his ability was more due to anticipation as a result of practice than an innate ability. For instance, batters do anticipate at least partly on the basis of previous balls and strikes against them. Laboratory-based research has found that batters’ decision-making processes were 60ms faster when they had this “count information” compared with when it wasn’t available (Farrow & Kemp, 2003). McGwire may have had one advantage, however: in 2010 he publicly admitted to using performance-enhancing drugs throughout his career. David Donner

The A - Z of Sports Vision - Quantum Biology

“Q” should really be for the Quiet Eye, but as I've already talked about that, it’s an opportunity to talk about a sport that’s rarely mentioned in terms of sports vision – pigeon racing. The term quantum biology was first coined by Edwin Schrödinger (of Schrödinger’s cat fame) in 1944. It’s always seemed miraculous that birds are able to navigate so accurately over such long distances. It’s been assumed that they do this by using the earth’s magnetic field, but it’s only recently that our understanding of quantum physics has enabled us to speculate on how they actually do it. As soon as one enters the world of quantum physics, things start to get seriously weird pretty quickly. For instance, in quantum superposition, particles can have different states such as a particle or a wave, until you observe them. To take the idea to an absurd level, Schrödinger suggested that a cat in a sealed box could be both alive and dead until the box was opened. There is also the phenomenon of “entanglement” in which unconnected particles influence each other, so that measuring one affects the measurements of the other. It’s this process of entanglement that is thought to take place within the bird’s retina that enables it to navigate. The idea is that a photon entering the bird’s eye releases a pair of molecules, each with an unpaired electron. Each of these electrons has an angular velocity, or spin, that can be altered by a magnetic field. Under quantum entanglement, the spin of one electron will affect the spin of the other, no matter how far apart they are. The birds might even have an image of the magnetic field that overlaps the visual image. So far, the only suggested use of quantum biology in humans is that it may explain how we are able to distinguish different smells. But it’s early days; who knows what we may find out in the future? David Donner

The A - Z of Sports Vision - Paralysis by Analysis

Take something you do every day without thinking about it – brushing your teeth, for instance, Next time you brush your teeth try and think about the precise movements that you are making with your hand. If you manage to keep this up for a while, you’ll find that brushing your teeth is no longer the simple process that it was on the previous occasion. If you start thinking about the mechanics of a routine process that we normally do sub-consciously, the result is that our performance deteriorates: “paralysis by analysis”. This is particularly common in sport: when something goes wrong, it’s very tempting to start analysing the mechanics of what happened, with the result that a blip becomes a catastrophe. Jackson & Beilock (2008) asked skilled soccer players to dribble the ball through a series of pylons while paying attention to the side of their foot that most recently contacted the ball. Their performance was worse in terms of being slower and having more errors compared with when they were given no instructions. Similar results have been found in baseball where skilled university-level players were asked to perform a hitting task. They heard a randomly presented noise and were told to indicate whether their bat was moving up or down at the instant they heard the noise. Biomechanical swing analysis revealed that the resultant deterioration in performance was at least in part due to a disruption in the sequencing and timing of the components of their swing. The more complex the skill, the greater is likely to be the loss of performance when the player concentrates on the step-by-step components of that skill (Masters et al 1993). It’s also more likely to occur in a high pressure situation, such as hitting a golf putt to win a golf championship (Masters et al, 1993). And it’s golf, and in particular Tiger Woods, that has given us an example of how paralysis by analysis can be overcome. Tiger’s father Earl taught him to putt when he was just a toddler. He told him to rotate his head and really look at the hole, then come back to the ball. He repeated this two or three times until he built up a picture in his head. All he had to do now was to “putt to the picture”. In other words you want to tell your subconscious brain, in as much detail as possible, exactly what you want it to do. But don’t tell it how to do it. David Donner

The A - Z of Sports Vision - Occlusion

Andy Murray is generally reckoned to be the best service returner in the world. He achieves this because he is the best at anticipating the opponent’s serve. How does he do that? One of the best ways of finding out is by occluding the vision of experts so that they can only see part of the opponent’s service action. These experiments have shown that experts can predict the direction of a serve before the racket makes contact with the ball. They are able to use cues such as the motion of the arm holding the racket that occur early in the opponent’s service action (Abernethy & Russell, 1987). The next step has been to see if lesser players can be trained to anticipate better by having their vision occluded at crucial points. Farrow & Abernethy (2002) put this to the test with 32 intermediate-level schoolboy tennis players. They were tested before and after training, with a retention test 32 days later. The tests consisted of facing actual tennis serves on a court whilst wearing occlusion goggles that cut off their sight at various points from 900ms before the server’s racket hit the ball, to a time after contact when the ball was approaching the net. They anticipation was judged according to the direction of the first movement they made as they attempted to return the serve (even though they couldn't actually see it at that point). During training, they watched video clips of serves that were occluded at various points. They had to say immediately where they thought the serve was directed. They would then watch it again when there was no occlusion, so they could assess how accurate they had been. One group was given specific information about the anticipatory cues used by experts, such as the location of the ball toss and the racket head angle just before contact (explicit knowledge), whilst a second group was not given this information but had to estimate the speed of each occluded serve (implicit knowledge). A placebo group did not have video training, but watched videos of tennis matches for an equivalent time. There was also a control group that didn't watch any videos. All four groups also had physical tennis training as well during the 4 weeks. The only group that showed a significant improvement in their anticipation was the implicit training group. They showed an improvement when their vision was occluded after the ball had been tossed, but before contact was made. This period has been shown to be crucial for service prediction (Farrow, Abernethy & Jackson, 2005). The placebo and control groups showed no improvement. Although the explicit group had high scores on average, they did not show an improvement in anticipation. This could be because they had too much information, whereas the implicit group concentrated on the racket movement in order to estimate the speed of the serve, and this was also the best indicator of the serve’s direction. Similar improvements from occlusion training have been found for baseball hitters (Fadde, 2006). Other sports will no doubt catch up in time: for example, there is no reason why it shouldn't be used to help goalkeepers trying to save penalties. David Donner

The A - Z of Sports Vision - Neurons

The normal adult brain contains around 85 billion nerve cells or neurons, each with between 1,000 and 10,000 connections to other cells, via between 100 trillion and 1,000 trillion synaptic connections. If that wasn't mind-boggling enough, consider what’s going on in the unborn foetus. In the last month of pregnancy, new neurons appear and migrate to where they are needed at the rate of 250,000 per second, resulting in almost a trillion cells at birth. These neurons are then rapidly pruned down to the 85 billion or so that we have for the rest of our life. Studies have compared the brain structures of animals raised in various environmentally normal, deprived or enriched settings. The enriched settings provided the opportunity to interact with toys, treadmills and obstacle courses. Animals placed in enriched environments had brains that were larger and contained more synaptic connections. By contrast, studies Romanian orphans (Chugani et al, 2001 for example) show significant reduced brain function as well as a smaller brain size compared with children who were adopted. As the baby explores and interacts with its environment, the neurons in its brain transmit signals to each other. To achieve the precision of the mature brain, stimulation in the form of movement and sensory experiences during the early developing years is necessary. Experience appears to exert its effects by strengthening and bonding synapses – the connections between neurons. The neural networks that are used get stronger, those that are not wither away, just as unused brain cells start dying in the first weeks after birth. Due to differences in experience, not even identical twins are wired the same. This interplay is life-long. Even the adult brain can continue to re-wire itself and make connections after exposure to new situations. The more that a particular brain network is activated the stronger the signal becomes (external stimuli send electrical impulses racing from one part of the brain to another). The brain consolidates learning by pruning away synapses and wrapping myelin around other connections to stabilise and strengthen them. At some point the signal becomes so strong and stable that these connections cannot be pruned away. Myelin is thought to be crucial in developing expert-level skills. The thicker the myelin gets, the better it insulates and the faster and more accurately the signals travel. It’s this that seems to be the key to developing a reliable golf swing or tennis serve. There’s increasing evidence that physical activity is one of the main ways the brain develops, with greater neuron and synapse production (for instance Gould et al, 1999, 2000, 2004). It seems there can be even greater rewards when decision making is involved with extensive practice (Brown et al 2003). Draganski et al (2004) used fMRI scans to examine the effect of juggling on brain development. After three months of juggling, a significant increase in grey matter (un-myelinated nerve cells) was detected in the occipital cortex and visual areas of jugglers compared with non-jugglers. If you really want to give your kids a head start in terms of hand-eye coordination, teach them to juggle. David Donner

The A - Z of Sports Vision - Music

In 2008, the US Track and Field (USATF) banned headphones and other music-playing devices at all USATF-sanctioned running events. This was for safety reasons, because athletes wearing headphones might not hear instructions from officials, other athletes trying to overtake them, or even road traffic in some cases. Many other organisers have since followed suit, but some athletes say they would rather not race than be without their MP3 players. That’s because music can aid sporting performance in a number of ways. Firstly, music can divert the mind from feelings of fatigue. For instance, Karageorghis & Terry (1999) found a 10% reduction in perceived exertion during running on a treadmill. This only works if the exercise isn’t too vigorous. But even then, although there’s no reduction in the perceived effort, the runner is still likely to find it a more pleasurable experience compared with no music. In 2009, a study of female basketball players in Australia found players who had a tendency to choke were significantly more accurate in free-throw shooting during high pressure situations if they first listened to “Always Look on the Bright Side of Life” from “Life of Brian”. It seems that the music distracted them from thinking about the mechanics of their throw. Music can also be used to get the athlete into their preferred mental state before a completion. Although for some this might be something upbeat to get the adrenaline flowing, others use it to stay relaxed. For instance Dame Kelly Holmes used the soulful ballads of Alicia Keys in her pre-event routine at the Athens Olympics in 2004. Karageorghis & Lee (2001) found that a combination of music and imagery enabled participants to hold on to weights for longer when compared with music or imagery alone or neither. Performing at the same tempo as the music has been found to be advantageous in a number of sports. Bacon, Myers & Karageorghis (2008) found that cyclists required 7% less oxygen to do the same work when they cycled in time to music compared with when they just listened to background music that was asynchronous (not at the same tempo). In February 1998, Haile Gebrselassie of Ethiopia smashed the indoor world record for 2,000 metres while listening to the rhythmical pop song “Scatman”, which was played over loud speakers. Music can also be used to enhance young athletes’ motor skills. For example, “Push It” by Salt-n-Pepa helps athletes hone shot-putt technique. The lyric reinforces the need for athletes to putt (i.e. push) the shot rather than trying to throw it, the most common technical error. Finally, music can help athletes get “in the zone” (also known as “flow”). Pates, Karageorghis, Fryer & Maynard (2003) looked at the effect of pre-task music on the performance of three college netball players. Two reported an increase in their perception of flow, and all three showed considerable improvement in shooting performance. David Donner

The A - Z of Sports Vision - Long Loop Reflexes

There are several different kinds of reflexes in the human body. Short loop reflexes involve just one nerve junction or synapse. An example is the well-known knee-jerk reaction. This occurs if a leg, swinging free, is tapped at the patellar ligament, just below the knee. A nerve signal is sent to the spine that the ligament has gone slack, as happens when you start to fall over. This signal reaches the spinal cord where, on the other side of the synapse, a responding nerve signal is sent out to make the quadriceps muscle contract. If you were falling, this would propel you into the air and give you a chance to regain your balance. When the doctor does it, you just kick your leg out. But there are also reflexes which involve several synapses. An example is the withdrawal reflex that ensures that you move your hand away rapidly if you touch a hot object. Pain receptors in the affected area send a nerve impulse to the spinal cord, which relays the message to the nerves that control flexor muscles in that area. A third nerve impulse results in that part of the body withdrawing from the painful stimulus. All this takes about half a second, before you are consciously aware that it’s happened. In sport, the connection between the stimulus and the reflex is usually less direct, for example a goalkeeper having to adjust to save a deflected shot. These kinds of actions are known as long loop reflexes because they have some involvement of the brain, rather than just in and out of the spinal column. Wayne Gretzky is generally acknowledged to have been the greatest ice hockey player ever. He played in the National Hockey League for 20 seasons, and holds the career record for total points scored (goals and assists) and assists. And yet Gretzky was always the runt of the team. Small, skinny, slow and with a weak shot. He didn’t even have the most accurate shot, although he was accurate. But he was the fastest at initiating a shot when he saw the opportunity to score, such as from a rebound. He also had the fastest long loop reflex times of anyone examined at the University of Columbia laboratories in Canada. It’s possible that these exceptional reflexes were just a genetic fluke. However it’s also possible that stimulation, particularly at a young age, is crucial. And there are few better examples of stimulation at a young age than Wayne Gretzky. Almost as soon as he could walk he was sliding around the floor in his socks, pretending to skate. He was skating on ice at the age of two on a frozen river that ran through his grandparents’ farm. He practised shots with a rubber ball and a cut-down hockey stick. His father built a rink in the family’s back yard and invited the neighbouring kids to play where he spent thousands of hours. He was ready to play junior league hockey at the age of 5, but had to wait until he was 6 before a team would take him, even though the minimum age was supposed to be 10. When he was 10, he scored 378 goals in a season. Asking how much of a player’s success is down to nature and how much to nurture is like asking how much of the flavour of a cake is down to its ingredients and how much is due to the cooking. But it seems highly unlikely that Gretzky would have been as good a player if he had not had essentially unlimited practice time in those early years. And the same is probably true of those exceptionally fast long loop reflexes. David Donner