Objectives. This study compares the effects of progressive muscle relaxation and an imagery-based relaxation training on childrens' physiological and subjective responses in a randomized controlled trial.
Design. Sixty-four children aged 9 to 13 years were randomly allocated to either one of three experimental conditions: progressive muscle relaxation, imagery-based relaxation or a control condition (neutral story). There were five training sessions in each condition.
Method. Heart rate (HR), skin conductance level (SCL), and skin temperature (ST) were measured continuously during a 5-minute baseline period, an 8-minute relaxation training period, and a 5-minute follow-up in each session. In addition, subjective ratings of mood and physical well-being were collected intermittently.
Results and conclusions. A physiological pattern indicating relaxation was most clearly associated with the imagery-based relaxation approach (decreases in HR and SCL), although ST remained unchanged. In contrast, progressive muscle relaxation led to an increase in HR during the training. The neutral story condition showed a similar trend as the imagery-based relaxation approach (although not reaching statistical significance). Furthermore, children's ratings of positive mood and physical wellbeing increased during baseline and training periods, but there were no differences between training conditions. The results indicate psychophysiological effects of relaxation instructions which, however, are not specific for systematic relaxation training.