Efficacy of Abbreviated Progressive Muscle Relaxation in a High-Stress College Sample

This study's purpose was to examine the efficacy of abbreviated progressive muscle relaxation (APMR) to enhance physiological and psychological functioning among high-stress college students. Participants ( N = 128) were undergraduates, 19 years old on average, predominantly female and White, with high Perceived Stress Scale scores. After random assignment, for 20 min, 66 experimental group participants underwent APMR lying down and 62 control group participants lied down quietly. Pre- and postintervention measures included the Endler Multidimensional Anxiety Scale, relaxation items, electrocardiograph heart rate and heart rate variability (HRV), and salivary cortisol. Compared with the control group, the experimental group demonstrated significantly greater increases in mental (Cohen's d = 0.32) and physical (Cohen's d = 0.32) relaxation, and normalized high-frequency HRV (Cohen's d = 0.29), and decreases in low- to high-frequency HRV ratio (Cohen's d = 0.31). Small effect sizes were observed for anxiety, normalized low-frequency HRV, and cortisol. Analyses of the reliability and clinical significance of these changes indicate trends in the expected direction. These findings indicate an APMR intervention can have significant short-term effects, both reducing detrimental and enhancing beneficial functioning in high-stress college students.