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The beauty of curling
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We have known for some time that sporting performance is related to visual function.1 It has also been established that sporting performance is influenced by factors including uncorrected ametropia2 and eye dominance.
Alongside this we are continually trying to understand which factors of visual performance influence success in the sporting arena. Is it necessary to carry out full sports vision assessments to assess an athlete's vision? How accurately does visual performance map sporting performance? This article examines the relationship between results obtained during sports vision assessments and subsequent sporting performances. As you will see, the results point to some interesting relationships.
The data was obtained during sports vision assessments carried out by the author in private practice on a group of athletes from the Scottish Institute of Sport. The athletes then went on to compete in the curling tournament at the Winter Olympics in Salt Lake City. The athletes screened included the Gold Medal winning team of Rhona Martin. All athletes' results presented are done so anonymously.
The sports vision assessment
The sports vision assessments can be broken down into four main categories: visual skills, focusing ability, reaction times and hand/eye co-ordination. A brief outline of each category follows:
- Visual skills: Includes assessment of VA, refraction, contrast sensitivity and stereopsis. Any significant refraction was corrected using spectacles or contact lenses. Appropriate advice was given on contrast-enhancing tints and filters
- Focusing ability: Includes measurement of accommodation and convergence, using tests including the accommodative rock and brock string
- Reaction times: These measurements were taken using specially adapted keypads and foot pedals linked to a laptop computer
- Hand/eye co-ordination: various measurements were taken, simulating both training and game situations. These were done using the Dynavision 20003 saccadic fixator.
Dynavision 2000
Each individual assessment lasted approximately two hours. Following the initial session, data was analysed and each athlete given a set of scores. These scores were all marked out of 100, with a score for each of the four sections and then an overall score. These scores can then be used to rank an individual next to their fellow athletes. It also highlighted which athletes were suitable for certain tasks. This data also forms the basis of any visual training programme designed for an athlete.
Curling - a brief guide
Curling is a competition between two teams with four players each.4 The game is played on ice, and the two teams take turns pushing a 19.1kg stone towards a series of concentric circles. The object is to get the stone as close to the centre of the circles as possible.
Delivery of the stone, with players ready to sweep
One game consists of 10 'ends'. During each end, each team delivers eight stones - two stones per person. The team members deliver the stones in a set order presented to the officials before the game. The first player is known as the 'lead'. He/she is followed by the 'second,' then the 'third' (also known as the 'vice-skip') and finally the 'skip', who is the leader of the team. Each end starts with the leads alternating throws until they have each thrown their two stones. They are followed by the seconds in the same manner, and so on. Team members not currently delivering the stone follow the stone down the ice and sweep the ice to help control the speed of the stone.
The score for the end is determined when all 16 stones have been delivered. The team that scores in an end shoots first in the next end. The team with the most points at the conclusion of 10 ends is the winner. Due to the varied elements involved in curling there are varying visual demands, including aiming, balance, hand and foot to eye co-ordination.
Why curling?
One of the major difficulties in assessing the effect of vision on sporting performance is how to assess the sporting performance itself? For many popular sports such as football, cricket or rugby, assessing an individual's performance is difficult. This is particularly true for team sports.
What do we use as the indicators of performance? In football do we use goals scored? Or in rugby the number of tackles made? Or the team results? As you can imagine, these markers are all greatly affected by outside factors. Variables such as the position a player was in, the amount of time they were in possession, and their team mates' actions all have a bearing on performance. There is also no standard way of recording performance in many sports. A player may be given a rating but there is no standardised way of grading performance.
The beauty of curling for this purpose is that for each game an individual scores points, marked out of 100, which accurately reflects their performance. This makes it ideal for comparison of performance and visual skills. It was also preferable to use a group of locally-accessible athletes, performing at an elite (Olympic) level, in a sport encompassing many different elements and visual tasks.
Results
Each player was graded for the individual section and then a total calculated from the average of these four results (Figure 3).
The team took part in 10 games or 'draws' during the competition (results courtesy of worldcurling.org5). Each player received a score for any game they took part in (as you can see, not every player featured in every game as the composition of the team changed). These scores were then averaged to give an indicator of the athletes' overall performance (Figure 4).
Conclusions
The results of this study show a good correlation between results obtained in sports vision assessments and subsequent sporting competition. This leads us to the following conclusions:
- Detailed sports vision assessments are an accurate way to fully understand an athlete's visual system. Results from these assessments can be used in many ways
- In this study, these results were shown to be a good predictor of sporting performance
- Following sports vision assessment, athletes using specifically-designed visual training regimes could improve their performance
- Sports vision could potentially be used as an indicator of future sporting performance. This could be especially useful as part of a screening programme for junior athletes, which may include other (non-ocular) assessments also.
Acknowledgements
Thanks to The Scottish Institute of Sport, and in particular Mike Hay and Cate Brewster for their help in compiling this research
References
- Griffiths GW. Eye dominance in sport: A comparative study OT Optometry Today/Optics Today, 2003 43:16
- Griffiths GW. The incidence of ametropia in elite sport: a comparative study OT Optometry Today/Optics Today, 2005 29:17
- www.dynavision2000.com
- www.olympic.org
- www.worldcurling.org
● Colin Moulson is a sports vision optometrist in Glasgow
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