Visual control of trajectory orientation
To orient while skiing is to look towards a specific point of the slope. Controlling our trajectories is regulating our motion, taking the ground optical flow and the lamellar flow as references. While orienting on a ski slope we guide our gaze towards the destination point, which is normally located about the distant zone. Instead, to control our immediate path, our gaze is directed at nearly the proximal zone to perceive snow surface and ground irregularities.
Visual perception in ski racing
In ski racing, like any other speed motion sport, athletes’ efficacy, among other aspects, highly depends on the relationship between visual perception and action. An effective visual perception in ski racers is essential for their performance
Our visual behavior for steering the skis could be defined in two strategies: the guidance strategy is based on information about the anticipated path. The stabilization strategy is on adjusting steering to possible deviations from the chosen trajectory, acting as compensatory control. In racing, these two strategies involve that the stabilization strategy is employed when directing gaze towards the next gate for immediate control, where the guidance level is oriented to upcoming gates, providing information on the future path.
The visual buffer is the time period between the visual fixation to the gate and the moment the racer gets to it. It is the moment in which visual information is kept in short-term memory while moving in the curvilinear path of a slalom course. During visual buffering, the racer collects information about how to best accomplish the turn. The longer the curve, the more time the visual buffer will consume. The problem arises when taking longer than the appropriate time needed; then, he will be late at executing the next turn initiation because of the delayed gaze shifting to the next gate.
In a study about visual perception in ski racers, Schläppi et al (2016) concluded that certain racers may not be able to describe where exactly they point their gaze when going down a slalom course. Some direct it towards the next gate, or to the area close to it, while others look further gates ahead. Actively looking more than two gates ahead appears to be not suitable, obviously, this will depend on the discipline, the speed, the course layout, and the racer’s visual skills.
Slower racers tend to direct their gaze toward the proximal zone, i.e., the area between themselves and the immediate gate. Expert racers focus more on the second next gate and on timing, while novices tend to do it on snow surface and on movement execution. Also, they tend to focus the immediate gate with foveal vision, while experts focus every first and third gates with peripheral vision, leaving foveal vision oriented towards every second gates down the course.
According to a study by Decroixa et al. (2017), visual attention distribution differs for experts and non-experts racers. Experts fixated the gates 91% of the time and 9% to the area between them, whereas non-experts looked at the gates 75% of the time and 25% at the snow in between. The authors conclude that this may be the difference between experts and novice racers’ performance.
Also, perceiving the perpendicularity of poles’ position collaborates with the ‘upright’ perception of certain objects in the environment, the visual fixation for postural balance, and head verticality.
Visual strategies in racing
We mentioned that optimal visual perception enhances race performance. Everyone could agree that visual anticipation (looking ahead) is a must since, for a more stable run, it allows being “one step ahead of what is coming”. The visual strategy characteristics could be, in some racers, different from training than racing related to their psychological state, weather, and course conditions. At the race, vision is part of the automated motor mechanisms as an “automatic gaze control”.
According to studies on this topic (Schläppi et al, 2016; Decroixa et al., 2017) racers would apply different visual strategies when skiing a slalom course. Some apply an in-between strategy of looking at the gate for orientation and looking at the path for gate line anticipation, alternating vision among these two spots. Other racers look systematically at the bottom of the next gate.
Excessive looking at the ground with foveal vision is a source of slower skiing. This may happen when the course is in poor condition. If it is in good condition, then the racer is prone to look at the coming gates. Regarding course inspection, some athletes memorize specific key sections, and this helps recognizing them immediately as approaching.
Other aspects that influence visual strategies in racing are:
- Course condition.
- Upper body inclination.
- The distance between gates.
- Speed
- Mental condition.
- Fatigue
- Weather visibility.
Poor weather visibility could make the difference. The racer who better adapts to a shadowed course line takes more advantage. Also, there is a tendency to lean back in poor visibility, which could diminish the ‘go for it’ attitude. In this case, the racer’s visual memory of the course inspection may be helpful. In foggy conditions, there is a tendency to look at the path when the gates are further apart from each other. It is also important to note that at high speeds, due to markedly course ruts, skis vibration disturbs visual perception affecting the precise visual fixation of the gates’ location.
Being alert and focused are the main ingredients in racing visual strategies, which are practiced in training as well as coaches discuss with their athletes about how to better use these features.
