Modification of the Activity of the Prefrontal Cortex by Virtual Distraction in the Lumbago

The hypothesis of this work is that distraction is an effective way to modify the feeling and experience of chronic lumbar pain by modifying the functioning of the prefrontal cortex. The main objective of this study is to show that during chronic low back pain generated during physical exercise, virtual reality distraction leads to the modification of the activity of the prefrontal cortex. The secondary objectives are: * Show a significant decrease in the average pain assessed with EVA during physical exercise with virtual reality distraction. * Show an increase in the distance travelled with virtual reality distraction. * Observe a decrease in perceived effort with virtual reality distraction. * Quantify the adherence (presence) of subjects to the virtual environment