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Visual Fitness

post #1 of 5
Thread Starter 
In light of my recent experience with low visability in Utah, and of skierteach's post in Community affairs about National Eye Care Month, I've been doing a bit of research.

Extroceptors and Proprioceptors are responsible for transmitting feedback to the nervous system, which in turn influences how movements connect throughout the kinetic chain.

Extroceptors receive input from outside the body.

Proprioceptors receive input from inside.

Successful skiing is dependent on how well the skier can synchronize the input from both sources.


The EYES, being the chief extroceptive organ are responsible for 2 primary systems of movement control.

The FOCAL system is involved with the identification of objects. “Is that a tree or a snowboarder up ahead?” Light plays a major part in thee functionality of the focal system. This is evident in the challenge of skiing in the late afternoon, in flat light.

The AMBIENT system takes in the central and peripheral visual field. It perceives movement and position of people and objects in the environment. “How close is that boarder to me?”

OPTICAL FLOW: Optical flow” describes the reflections of light which pass through the eye from your environment. It provides information about the skier’s movement in that environment. This includes the skier’s stability and balance, the velocity of their movement, the direction of the movement in relationship to other skiers in the environment, and the time of contact before the skier and an object, such as a tree or lift pole, or another snow sport enthusiast. This may possibly explain the number of ski accidents that happen in the late afternoon, in flat light.
Sometimes a postural issue such as the forward head, a major cause of misalignment in skiers, can possibly be caused by visual problems. But sometimes, head and neck alignment is responsible for poor vision.

Most recreational athletes do not consider vision training an essential part of their sport-conditioning program. But think about the visual challenges that are presented throughout a typical ski run. Trees, snowboarders, other skiers, and families of 7 appear out of nowhere. Flat light in the later part of the afternoon imposes different sorts of challenges. Skiers need to shift their gaze smoothly and rapidly, from points in the distance to points in proximity. The ability to see changes in terrain enables a skier to plan, and react appropriately. 80% of the information we receive is visual. Improving visual skill can enhance motor coordination.

When the eyes send visual information to the brain. The brain integrates this visual data, and presents it as a 3 dimensional image. This process is called fusion. If a skier is not focusing on something specific, such as a tree or a slalom gate, their eyes will move throughout the entire visual field. If something of importance catches the skier’s attention, they will focus on that object. The process of focusing on something specific is called fixation. But studies have found that the average range of focus is approximately 3 degrees. Since the focus of the visual field is so small, peripheral vision becomes a crucial aspect of sport vision. Anyone who has ever been “side swiped” by another snow sports enthusiast understands this.

Determining eye dominance is also important. Your dominant eye transmits and processes visual input a few milliseconds prior to the opposite eye. Make a triangle with your two index fingers. Extend your arms at shoulder height and frame a small object in the distance with your triangle. Close one eye and focus at the object. Whichever eye centers the object in the window of the triangle is your dominant eye.

Different types of eye movements are used to track various types of athletic movement. Saccadic eye movement is used in rapid scanning. Vestibulo-ocular movements integrate eye movement with head movement, and assist with balance. Vergence eye movements focus on objects moving in the distance. Smooth pursuit eye movements follow objects moving in slow motion.
Saccadic eye movement decreases with age. This can cause increased blinking, which may in turn cause errors in visual tracking. A study conducted in 1980 showed that anxiety will cause increased blinking in athletes. Since blinking causes the eyes to be closed for about 1/10 of a second, serious errors of visual judgment can occur.

Static visual acuity refers to the ability to the ability to discern stationary detail in an object. Some of the factors influencing static visual acuity are color, light, contrast and motion. While greater illumination can improve acuity, too much glare can interfere with it. Dynamic visual acuity refers to the ability to discern detail in objects in motion. While it varies in each individual, studies have shown that dynamic visual acuity improves with training.

Check out the Visual Fitness Institute for some articles about their work with the US Ski Team, as well as some interesting visual fitness exercises.
post #2 of 5
In collisions I have long believed that fixation can cause both skiers involved in a collision to fail to see the other until it is too late. This happens because the skiers are focusing on an object or point down hill and the peripheral vision is being overridden by the brains excessive focus on that small focal point. As skier experience and age (up to a point) increases this seems to lessen. Young, inexperienced skiers seem to fall prey to this type of collision quite readily.

post #3 of 5
Thread Starter 
Yes! Ironically, I 've noticed this happen when novice skiers become so focused on a collision that they either join it, or collide into someone else!
post #4 of 5
Ha, this is the key problem with newby tree skiers. They fixate on the trees and then wonder why they are always having to take evasive action to avoid the trees.

Tree skiing is easy. Just ski where the trees aren't. And to do that you must look where the trees aren't!


[ February 09, 2004, 11:01 AM: Message edited by: Maddog1959 ]
post #5 of 5
Thread Starter 
One of the greatest tips I learned early on is that your body will follow your eyes. Keep staring down at the snow, guess where ya' end up?

The most important lesson I learned in Utah is to always have a set of lighter lenses available. Darker lenses in very flat light can create a mirage on a cattrack. It looks like its finally opening up into a trail. NOT!! YIKES!!
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