Standardized massage interventions as protocols for the induction of psychophysiological relaxation in the laboratory: a block randomized, controlled trial

Figures

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  Figure 1. Changes in subjective relaxation ratings across the experiment in the three different experimental conditions vagus nerve massage (VNM; n = 19), soft shoulder massage (SSM; n = 22) and resting control group (RCG; n = 19). The intervention interval is shaded. Values are depicted as means ± SE. Time represents the within subject factor in the mixed Analysis of Variance. * indicates p < 0.001 in a post-hoc t-test comparing the timepoints pre intervention and post intervention across all experimental groups.

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  Figure 2. Changes in high frequency heart rate variability [ln(HF-HRV) in ln(ms2)] across the experiment in the three different experimental conditions vagus nerve massage (VNM; n = 19), soft shoulder massage (SSM; n = 22) and resting control group (RCG; n = 19). The intervention interval is shaded. Values are depicted as means ± SE. Time3 × Touch Effect represents the interaction between the cubic effect of time and Touch Effect (a dummy variable indicating resting control group = 0, soft shoulder massage = 1, vagus nerve massage = 1). Time3 × Vagus Effect represents the interaction between the cubic effect of time and Vagus Effect (a dummy variable indicating soft shoulder massage = 0, vagus nerve massage = 1).

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  Figure 3. Flow diagram visualizing the sample of the study.

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  Figure 4. Overview of the study procedure. HR heart rate monitoring, PSQ Perceived Stress Questionnaire. During the intervention, participants were randomly assigned to either a vagus nerve massage, a soft shoulder massage, or a resting control group. For subsequent heart rate variability analysis, the periods of interest were split up into 2.5 min segments as depicted in the figure to allow for a higher temporal resolution of heart rate variability changes.