Vision care for athletes should begin with the identification of visual factors that potentially contribute to peak human performance so that these specific functions can be isolated and measured, if possible. The visual demands critical to success in sports can vary tremendously. For example, a dynamic and reactive sport such as basketball has very different visual demands than the static precision requirements of target shooting. This chapter provides an approach to this task analysis process, which is essential to provide appropriate vision care for athletes in any sport or position.
A practitioner’s depth of knowledge concerning a sport activity provides the foundation for delivering the highest quality vision care for the athlete. Personal participation in the sport activity by the practitioner offers the most intimate insights into the visual task demands encountered by the athlete. However, many crucial insights into the visual task demands of a sport activity can be acquired by extensive interaction with the athlete or other experts (e.g., coach, athletic trainer) in the sport. These insights can be further supplemented by observation of the sport activity, which may offer the opportunity for a personal experience. For example, the first time the author worked with a skeet shooter, extensive interaction with the athlete was necessary because the author had no personal experience with this sport. This interaction was followed up with a visit to the shooting range for observation of the activity and personal experience to gain further insights into the visual task demands of skeet shooting.
Many other avenues are available for information concerning the demands of a specific sport activity. The American Optometric Association (AOA) Sports and Performance Vision website offers a collection of detailed insights into the many visual factors involved in a variety of sports in the form of webinars, downloadable documents, and guidebooks. The sport-specific guidebooks were compiled with input from experienced optometric practitioners and are available with membership in the AOA. Information concerning less-common recreational activities can easily be found by searching on the Internet or consulting the many sports periodicals and books available. Consultation with a practitioner who has extensive experience with athletes in the sport activity can provide additional valuable insights for the task analysis process.
General Visual Characteristics of the Sport or Activity
Visual factors comprise the visual task demands of any sport activity. A series of task subcategories is presented and can be used to develop a profile of the salient features involved in a sport.
Static Versus Nonstatic
Static task demands are those in which the visual information is stationary, allowing for a steady image to be processed. Sport activities with static task demands include archery, target shooting sports, golf, free throw shooting in basketball, and free penalty shots on goal in soccer and hockey. These sport tasks allow the athlete to fine-tune the motor response based on stable visual information.
Nonstatic task demands are those in which the visual information is in motion, necessitating the constant processing of changes in the visual information. Many sport activities have nonstatic demands ( Box 2.1 ). For example, the running back in football does not typically have much time to study the defensive movements of the opponent before choosing a path to run.
Baseball
Softball
Basketball
Boxing
Cycling
Football
Hockey
Lacrosse
Martial arts
Motor racing
Racquet sports
Sailing
Skating
Skeet and trap shooting
Skiing
Soccer
Surfing
Water polo
Volleyball
Nondynamic Versus Dynamic
Dynamic is used in this chapter to describe the athlete during a sport activity. In many sports the athlete must perform while in motion ( Box 2.2 ). The hockey player must continue to process the action in a game despite being challenged to maintain balance while in motion, with constantly interrupted views of the action.
In nondynamic sports activities the athlete is relatively stationary when performing. Nondynamic sports include the examples listed in Box 2.2 . Even though movement occurs in golf during the swing at the ball, the athlete is allowed to analyze the visual information used to guide each stroke while remaining relatively motionless.
Sustaining Demands
The duration of the competition determines how long the athlete must sustain visual performance. In one study the majority of sports were determined to be completed within 2 h. Therefore many sports require sustained performance longer than 1 h ( Box 2.3 ). In a sport activity such as mountaineering, the ability to sustain a high level of visual information processing over many hours with little rest is not only an asset but also life protecting.
| Sustained Performance | Short Duration |
|---|---|
| Baseball and softball Basketball Boxing Cycling Football Golf Hockey Lacrosse Motor racing Mountaineering Racquet sports Sailing Nordic skiing Soccer Water polo Volleyball | Archery Baseball and softball batting Drag racing Fencing Gymnastics Speed and figure skating Skiing (alpine and jumping) Shooting sports Track-and-field events |
The duration of each individual event in some other sports is short, even though performance levels must be sustained for the length of the competition. These types of sports typically have significant rest intervals during the course of the competition, such as those listed in Box 2.3 . The demand on visual information processing is generally intense during the event, such as in alpine skiing, but the athlete is allowed a generous amount of time between events to rest.
Contrast Levels
The judgment of subtle contrast differences is a common visual task in sports. Contrast levels can be affected by changing illumination levels produced by weather, artificial illumination, shadows, glare, playing surface conditions, and backgrounds. Additionally, the relative contrast of the object is reduced any time the object is in motion, so that fast action sports tend be more demanding on contrast sensitivity. For example, a classic black-and-white patterned soccer ball has high contrast when stationary but significantly reduced contrast when kicked with a large amount of spin. Because the spin of the ball provides vital clues concerning its flight trajectory, the ability to discriminate the contrast of the ball pattern is potentially beneficial to the athlete ( Box 2.4 ). The selection of filters or refractive correction modality may also be affected by the contrast sensitivity demands of a sport (see Chapter 6 ). For example, the downhill skier must select the filter that provides optimal transmission characteristics to enhance relevant contrast information for the current light conditions.
Baseball
Softball
Basketball
Cycling
Football
Golf
Hockey
Lacrosse
Motor racing
Mountaineering
Racquet sports
Sailing
Skating
Skeet and trap shooting
Skiing
Soccer
Surfing
Water polo
Volleyball
The judgment of subtle contrast differences does not offer an advantage in some sports, such as archery, target shooting sports, and some track-and-field events.
Target Size
Significant differences may exist in the size of the visual information that must be discriminated in different sport activities. For example, the visual discrimination task for a hockey puck is much more demanding than that for a basketball. For each sport activity, the interaction between the size of the visual target or object and the viewing distances encountered in the sport should be evaluated to determine the visual discrimination demands. Significant interaction may also exist between visual discrimination level and contrast sensitivity demands. Again with the soccer example, the size of the soccer ball is relatively large, but the judgment of ball spin requires an enhanced level of visual discrimination than the ball size would suggest.
Distance Versus Near
The viewing distance where most of the visual information is received from can be analyzed to determine the vision demands for the athlete. In billiards, for example, the distances that must be clearly focused are fairly predictable. In other sports, such as hockey, the viewing distances may vary considerably during the course of the competition. Most sports have aspects that require clear vision for distances beyond 3 m ( Box 2.5 ). However, there are some sports that have aspects of the activity that involve near- and intermediate-distance focus.
| Far-Distance Demands | Near-Distance Demands |
|---|---|
| Archery Baseball and softball Basketball Cycling Football Golf Hockey Lacrosse Motor racing Mountaineering Racquet sports Sailing Shooting sports Skating Skiing Soccer Surfing Track-and-field events Water polo Volleyball | Billiards Boxing Cycling Martial arts Motor sports Shooting sports Wrestling |
Boundaries
Boundaries for the competition area are established in many sports. In some sports, such as table tennis and billiards, the boundaries are relatively small and can easily be seen during the competition. In other sports, such as soccer and football, the competitive boundaries are too large to be seen entirely at all times during competition. The extent of the boundaries establishes the peripheral vision demands for the athlete and may also affect the selection of refractive correction modality.
Visual Space Ranges
The athlete must attempt to control a range of physical space in many sports by constantly processing the visual information in that physical space. The physical space can be relatively confined, as in wrestling, or it may be much larger, as in sailing competitions. This factor also relates to the peripheral vision demands for the athlete.
Figure/Ground Color, Texture, Shade
An analysis of the figure/ground characteristics encountered in a sport can assist in the selection of filters to enhance performance. This aspect relates to contrast sensitivity, but is specific to color contrast demands. For example, a skeet or trap shooter must quickly locate an orange-colored target (sporting clay) against the background of the ground (brown dirt, green grass, brown grass, etc.), any foliage (trees, shrubbery, etc.), and the sky (blue sky, partly cloudy sky, heavily overcast sky, etc.). The selection of the optimal filter for the current light levels and backgrounds is an essential aspect of competitive skeet or trap shooting. Filter selection may offer significant benefits in many sports by sharpening contrast and enhancing critical visual information. Filters also offer a potential benefit by muting distracting visual “noise” from the background. Filter selection is discussed in detail in Chapter 6 .
Visual Time
Many sport situations have an established time course of action in which visual processing characteristics can be analyzed. The time course of a Major League Baseball pitch is one situation that has been scrutinized by researchers from a variety of backgrounds. , Depending on the speed of the pitch, the Major League batter has approximately 400 ms between the release of the pitch and the time the ball arrives at the plate. Because the swing takes approximately 150 ms to complete, the batter has approximately 250 ms to process the visual information from the pitch and decide on the appropriate response. These time characteristics are discussed in greater detail in Chapter 3 . However, many other sport situations have time characteristics that unfold in a relatively predictable manner. The serve in many racquet sports and volleyball, the pitch in cricket, penalty shots on goal in soccer and hockey, the judgment of hurdles in track, the judgment of the approach in high jump and pole vault in field events, the judgment of maneuvers in gymnastics and diving, and the flight of clay pigeons in skeet or trap shooting all have a range of time characteristics that define the visual processing demands for successful performance.
In other sport situations, the time course of the action can be less predictable (e.g., skiing, cycling, boxing, kayaking, motor sports, wrestling), thereby elevating the role of reactive visual information processing skills for success. Some sports have essentially no reactive component to the motor response (e.g., archery, target-shooting sports, golf, billiards). Many sports require development of the ability to modulate attention appropriately for success.
Directional Localization
In some sports the accuracy of directional localization is often critical to success. Directional localization is the ability to determine the exact direction of visual information (e.g., a target, object, opponent, teammate, terrain). For example, the ability to putt in golf requires the athlete to discriminate precisely the subtleties of the terrain for the shot to determine the best path for the putt. This skill requires the athlete, in part, to determine correctly the direction that the shot needs to take to account for the slope of the terrain and distance of the putt. Farnsworth discusses this aspect of golf in detail. Directional localization ability is a crucial feature for success, to varying degrees, in sports such as those listed in Box 2.6 .
