Acute effects of “Munz Floor”® fascial stretching on autonomic nervous responses assessed by heart rate variability

Purpose To analyze if the “Munz Floor”® fascial stretching method significantly modifies the autonomic nervous responses at rest. We tested the hypothesis of a positive influence on the parasympathetic activity. Methods Heart rate variability (HRV) was measured in thirty three (including nine females) healthy participants during a tilt test (i.e., 5-min supine followed by 5-min standing) before (pre-) and immediately after (post-) 60 min in either a control condition and 3 days later a “Munz Floor”® session. Time-domain (heart rate, HR); root mean square of the successive differences between RR intervals, (RMSSD), non-linear (standard deviations, SD1, SD2), and frequency-domain (spectral frequencies in very low, VLF; low, LF and high bands) parameters as well as the detrended fluctuation analysis (DFAα1) were measured. Results In supine position (SU), HR SU decreased to la larger extent (−12.4% ± 7.6% vs. −3.8% ± 4.0%, p < 0.001) in the “Munz Floor”® group (62.3 ± 8.7 vs. 54.4 ± 7.3 bpm, p < 0.001, Effect Size (ES) = 0.83) than in the control group (60.8 ± 8.7 vs. 58.4 ± 8.3 bpm, p < 0.01, ES = 0.27). Significant increases in RMSSD SU (50.1 ± 30.1 vs. 73.3 ± 48.0 m, p < 0.001, ES = 0.59), HF SU (1,212 ± 1,078 vs. 2,672 ± 2,388 m 2 , p < 0.001, ES = 0.72) were reported in the Munz Floor”® but not in the control group. In the standing position (ST): HR ST decreased in both the Munz Floor”® (76.6 ± 11.0 vs. 68.8 ± 9.6 bpm, p < 0.001, ES = 0.62) and the control (77.2 ± 12.7 vs. 74.7 ± 11.9 bpm, p < 0.01, ES = 0.20) but the relative change was larger in the “Munz Floor”® (−9.6% ± 9.4% vs. −2.9% ± 6.4%, p < 0.01). Significant increases in RMSSD ST (29.5 ± 23.8 vs. 39.9 ± 27.5, p < 0.01, ES = 0.38) and in (LF + HF) ST (2,132 ± 2,464 vs. 3,065 ± 3,382 m 2 , p < 0.01, ES = 0.31) were observed only in the “Munz Floor”® group. Conclusion The “Munz Floor”® fascial stretching method was effective for acutely increasing the parasympathetic activity. These results suggest “Munz Floor”® fascial stretching as a potential strategy for improving recovery and reducing the impact of stress and fatigue.