Sex-specific acute effects of postural hammock exercise on autonomic regulation and plantar pressure in individuals with low back pain

Abstract

Background: Low back pain is a leading cause of disability worldwide, with significant socioeconomic implications. The autonomic nervous system is implicated in the pathophysiology of back pain, with changes in heart rate variability (HRV) and plantar pressure observed in affected individuals. This study aimed to evaluate the effects of a single postural hammock-based exercise session on HRV and plantar pressure in individuals with low back pain. Methods: Forty-three participants (mean age 48.88 ± 11.87, 67 % women) with lower back pain were assessed before and after a 60-min exercise session, which incorporated flexibility, strength training, and deep breathing techniques designed to enhance autonomic regulation in a postural hammock. HRV was measured using a Polar heart monitor, and plantar pressure was analyzed with the Podoprint S4 System. Linear mixed-effects models were used to analyze the effects of the intervention, and subgroup analyses based on sex were performed using R Studio (v. 4.3). Results: The results indicated a significant reduction in heart rate (mean difference: − 5.2 bpm, p ≤ 0.01) and an increase in the HRV parameter very low frequency power (VLF; mean difference: 0.6 ms2, p ≤ 0.01), across all participants. No other HRV parameters showed significant changes. Women showed greater improvements in heart rate (mean difference: − 6.5 bpm, p ≤ 0.01) and VLF (mean difference: 0.6 ms2, p = 0.011) compared to men. However, no significant changes were observed in plantar pressure parameters. Conclusion: These findings suggest that a single session of postural hammock exercise may influence autonomic balance, particularly in women, but does not appear to affect plantar pressure in a static standing position. Further research is needed to explore the long-term benefits and mechanisms underlying these effects.