Relations between daily stressful events, exertion, heart rate variability, and thoracolumbar fascia deformability: a case report.

Background: The posture of performance-oriented sport climbers adapts in a way that likely promotes the development of low back pain. The thoracolumbar fascia, while also contributing to performance, seems to be involved in that process. Furthermore, there has been evidence of the stiffening of the fascial structures in disorders associated with negative affectivity. The study aims to investigate the relationship between the autonomic nervous system and the deformability of the thoracolumbar fascia in a sport climber in a natural setting.

Case presentation: Over a 30 day period, a 50-year-old German male reported daily morning resting heart rate variability and daily inventory of stressful events. The thoracolumbar fascia deformation was measured daily using ultrasound in a manual therapy clinic. A time series analysis was performed to detect possible time-delayed relationships between the variables. A cluster analyses revealed two distinguishable heart rate variability clusters (heart rate variability clusters 1 and 2). Both clusters were correlated with thoracolumbar fascia deformation and daily inventory of stressful events. Higher heart rate variability cluster 1 immediately caused lower thoracolumbar fascia deformation. Heart rate variability cluster 1 parameters mediated the effect of daily inventory of stressful events on a decrease in thoracolumbar fascia deformation with a 2-day delay. One heart rate variability cluster 2 parameter mediated the effect of daily inventory of stressful events on an increase in thoracolumbar fascia deformation with a 7-day delay.

Conclusion: Heart rate variability cluster 1 values, which probably indicate sympathetic nervous system activity, are directly related to thoracolumbar fascia. Presumably, the sympathetic nervous system mediated the effect of daily inventory of stressful events on a lower thoracolumbar fascia deformation with a 2-day delay, followed by a supercompensation, most likely parasympathetically mediated. Coaches and trainers should be aware of these mechanisms and consider monitoring during training to minimize potential additional risk factors for impaired performance and health.