In recent decades only, training methods have been developed to focus on plasticity, that is to say the modification, of the nervous system with a view to improving motor performance. Some involve the use of technologies which will prove to be a very good stimulant. Among these, virtual reality (VR) plays an increasingly important role. VR consists of the computer simulation of a three-dimensional environment with which a person can interact in a seemingly real or physical way, using special electronic equipment such as a headset with two integrated displays (one per eye) . Now well developed for leisure applications, let’s see how it can allow us to optimize the management of training, whether for a patient or a high-level athlete.
VR is used to simulate real situations while remaining in a safe context, such as to train future surgeons to perform delicate operations or with patients to simulate movements that are difficult to perform and/or vary practice environments while remaining in a hospital environment, for example in the context of rehabilitation . Regardless of the type of population and the type of intervention, the vast majority of authors agree that VR increases the benefits of physical practice. Let’s try to understand the effect that VR can have on an individual in its different dimensions associated with performance.
In addition to subjective assessments of psychological state, recording subjects’ physiological reactions also showed significant changes when using VR. One of the key measures used in VR is electrodermal activity, which is a classic measure of the effect of a stressful situation on an individual. Like lie detectors, the devices measure skin conductance, which is directly linked to sweating. This increases instantly with the slightest stress experienced . Thus, being immersed in a VR roller coaster immediately induces a significant stress response, demonstrated by the subjective feelings of individuals, but also by their physiological reaction, such as an increase in heart rate or of course the skin response.
VR is therefore a natural stressor for our autonomic nervous system, which controls the body’s vital functions (heart rate, breathing, etc.). Based on this fact, professional applications offer to prepare for a job interview by simulating it virtually, or to deal with arachnophobia by being confronted with virtual spiders. In sport, VR is also used to deal with certain stressful situations while remaining safe, such as going downhill while cycling at full speed. VR can also be used to simulate the atmosphere of a competition (noise, audience, music), a significant stress factor which often undermines sporting performance, even though it is repeated thousands of times in calm training.
Effects on cognitive functions
As VR seems to be a strong stimulant for brain functions, we asked ourselves the question of its effectiveness if used chronically on the performance of our brain. We carried out an experiment at the C3S laboratory at the University of Franche-Comté aimed at testing the effects of VR training coupled with physical exercise on the memorization, inhibition and attention functions of our brain.
Combining a video game, virtual or not, with physical exercise is called an “exergame”. So, is playing in VR beneficial for our brain abilities? The answer is yes. After training for only 5 days, for 15 minutes per day, the use of a virtual exergame (such as a dance game) makes it possible to increase specific performances of our brain, such as the time of reaction, inhibition or observation ability. The game used here consisted of cutting small cubes projected in front of the player at varying speeds and in different locations, using a saber in each hand, all while avoiding other projectiles (bombs). It therefore involves precise and rapid movements, associated with a detailed analysis of objects and choices to be made in a very short time (should I cut or avoid?). Conversely, practicing the same amount of physical activity alone (15 minutes per day for 5 days of similar movements, but without immersion and play), gave no results on these same functions. The added value of a VR game on the cognitive effects of exercise here is clear. These results can be explained by the additional playfulness and visual stimulation provided by VR.
Effects on the motor system
In addition to cognitive functions, when it comes to using such technology in training or rehabilitation of motor function, there arises the question of whether the effects can also extend to the neuromuscular system (which controls movements ). On this subject, electroencephalography (EEG) studies have given varied results. If VR is known to induce significant brain activation in sensory regions , this phenomenon is little studied with regard to the motor system (motor pathway from the cerebral motor area to the motor neurons of the spinal cord). There are a few rare studies on the subject, carried out in very specific situations. For example, VR would facilitate motor learning of sequences of finger movements performed virtually, or would help to stimulate the motor system in addition to traditional post-stroke rehabilitation.
Thus, the question of to what extent virtual reality can activate the motor system and, more specifically, whether it can affect neuromuscular performance, remains open. Recent results, however, are very promising. For example, we showed that a virtually simulated fall caused calf reflex activity to vary in the same way as during a real fall . Reflex activity (as tested by the doctor by tapping the tendon with a small hammer), is crucial for motor control. The latter being managed by the spinal cord, this shows that a virtual situation can induce modulation that goes well beyond the brain. The brain is therefore not the only one fooled by the virtual simulation… but a large part of the motor system. These results offer promising perspectives for the use of VR on motor function training. More particularly, this latest study shows that sports activities that involve jumping or running, movements for which the reflex activity of the legs is essential, could greatly benefit from VR. The intensive practice of jumps during training being very traumatic, particularly for the joints, VR would make it possible to increase the effects of training without increasing the physical workload.
Seduced by the idea of using VR in a training setting? Here are some tips and tricks to make the experience go as smoothly as possible and, above all, be effective. The effects of VR are, for example, very dependent on the individual’s receptivity to this intervention. The way in which a person reacts and interacts with various virtual environments thus depends on a certain number of technological and psychological characteristics.
The degree of immersion is, for example, determined by the technological characteristics of VR such as resolution, frame rate, or even field of vision. Thus, it is proven that more realistic graphics in a virtual environment have a positive effect on immersion .
So pay attention to the characteristics of the devices you use, taking for example the largest field of view (Field of View, or FOV: 100° being the minimum for better immersion), a good refresh rate, 60 Hz being the norm for seeing a smooth image, but higher is even better). The weight of the helmet can also be important, as it can be heavy to wear over the long term.
Some individuals have a better propensity to respond to VR: having an ability to immerse themselves in varied contexts, an ability to ignore distractions, the feeling of being “captivated”. This characteristic, which we call “the feeling of presence”, is usually assessed by questionnaire.
Another very important factor is the amount of sensory stimulation. The immersion effect is greater in the case of simultaneous stimulation of a greater number of sensory systems, the correspondence of stimulations of different modalities and its intensity. Matching the position of the individual with the simulated situation makes it possible, for example, to have proprioceptive sensory feedback congruent with the visual stimulation generated by VR (for example being seated for a virtual roller coaster). The ability to navigate freely in the virtual environment and interact with virtual objects (6 degrees of freedom systems, or DoF: degrees of Freedrom), when they are modeled realistically, also contributes greatly to the feeling of realism .
In addition to the contraindications inherent to broadcast content (such as certain videos or video games), such as visual sensitivity or even epilepsy if the content contains too many flashes of light, there is a very particular disorder which is specific to VR. Cyberkinetosis (or “cybersickness”, in English) is the fact of not tolerating virtual reality, of feeling nausea or dizziness. It is a sensory disorder which is in fact version 3.0 of seasickness (“motion sickness”). Cyberkinetosis results from sensory conflicts between vision and the balance system (the vestibular system in the inner ear). Thus, perceiving movements that do not correspond to real body movements can generate this type of disorder in certain particularly sensitive individuals.
VR appears to be a very powerful tool for stimulating the cardiovascular system, cognitive functions and the motor system. Added to exercise, it would, for example, increase cognitive demands, while making the effort more fun. This would result in significant gains in certain performances. You will have understood, in “virtual reality”, there is “reality”: the more realistic the VR effects are, the greater the gains will be. Associating sensory stimulation with VR that corresponds to the situation stimulated would also greatly increase the feeling of realism. For example, riding a virtual bike, while being on an exercise bike with a fan in front of us which simulates the wind…
Be careful, however, to use it sparingly, to avoid various problems! Like all technology, it should not replace real exercise if this is possible, but be a complement handled with intelligence. For example, even if very realistic in virtual reality, nothing beats a real walk in the forest…
Author Bio: Sidney Grospriest is a Lecturer in Neurophysiology at the University of Franche-Comté – UBFC