Decision-making time of falling avoidance
According to Berthoz & Petit (2003), when suffering a destabilizing perturbation, we do not have time to reflect on what to do, reacting according to the speed that our nervous system allows. Therefore, in approximately one hundred milliseconds, our brain processes various elements to make a decision such as direction, force, and speed of the imbalance perturbation; the recovery quickness; motion speed and/or path maintenance; other people or objects in the surroundings, or our memory of previous falls.
To avoid falling, we have three action possibilities: activate opposite side muscles of the potential fall, make a compensatory step, or find support on our poles. Based on previous experiences, while suffering a balance perturbation and choosing not taking a compensatory step or poles use to avoid the fall, we can predict the amount of muscle force needed to compensate for the disturbance by graduating the effort to resist the potential fall.
Falls categorization
Falls could be classified in the following:
- Accidental fall, resulting from causes not related to us, which is sporadical.
- The repeated fall expresses the persistence of factors that predispose it to inappropriate posture, prediction failure, or slow rebalancing reactions.
- Anticipated fall is the one which the beginner expects to have during his learning process and to the environment adaptation.
- A non-anticipated fall is the non-expected one and not predictable for the first time, but our intention will be preventing it.
Falling reflex
From birth we have an innate response to falls, contracting flexor muscles found in the front of our body, seeking a fetal position but this is only possible if our reaction time is enough, otherwise, we must adapt the best possible to the falling situation.
The sensation we had in our beginner’s stage about falling at any time was normal and it was due to the not much development of our sliding adaptation. This reaction was activated several times until it became a habit. When we reached the intermediate level, we skied trying continuously to avoid falling because we believed that was the way it should be and our body consciousness acted accordingly. Then, our postural attitude was not seeking balance but avoiding imbalance.
This falling reflex is compensated by the righting reflex, which is mainly activated at the initial sliding stages when we constantly perceived we could fall: our perception of a potential fall produces a disorder originating this reflex.
The perception of sliding surfaces determines the falling
Our immediate perception of the skiing surface is essential to prevent balance losses. Being on an inclined surface creates more chances of losing balance and falling because, at increasing slope angle, friction decreases. It is observed that, on many occasions, we are not conscious of the condition causing a fall. As an example, we restrict our skiing on ice, however, if we do not perceive beforehand its existence, probably we will lose our balance and fall.
Types and phases of falls
The different types of falls that are usually observed in skiing are the following:
- Forward, backward or sideways rotational fall: in this case, our body rotates over our BoS.
- The fall by collapse is produced by sudden legs relaxation. Our upper body quickly moves towards our feet, more exactly towards our heels as sitting on them, denoting our falling intention. It frequently occurs at beginner levels during the straight run as well as slope traversing.
- The free fall is characterized by the complete loss of body contact with the snow. It usually takes place when the skis suddenly accelerate forward, because of colliding with another person, rough contact with a bump, or hooking a ski tip in a gate while training or racing. In these cases, our body remains momentarily in the air before touching the snow again.
- Finally, it is noticed the combined fall,being the result of any combination of the previously mentioned falls.
In terms of phases, falls can be generally classified in the following, which of course are not structured but happen very quickly:
- First, we perceive the imbalance and the start of the fall followed by recovery mechanisms.
- Then, the fall itself.
- Finally, we activate mechanisms to prevent and/or mitigate potential injuries.
Fall avoidance and injury prevention
When experiencing an imbalance, we try first to avoid falling by recovering our balance, but if this cannot be achieved, then we start the necessary responses to attenuate the fall preventing a potential injury. Falling effects can be decreased, in some situations, when perceiving the impossibility of rebalancing. We accompany it letting ourselves fall since not all falling conditions are appropriate to avoid as this may be harmful. The trouble is that fall response mechanisms are automatic and occur before evaluating the consequences.
