This study aims to determine whether a brief video aiming to optimize expectations regarding the effectiveness of progressive muscle relaxation (PMR) can enhance the efficacy of a PMR session compared to a neutral video control group in an online intervention. Another aim is to assess whether this effect will be moderated by the degree of human support (guided or unguided intervention). After the baseline assessment, participants are randomized to one of 4 possible intervention groups: i) watching a video aiming to optimize participants' expectations before undergoing a single PMR session without personal support of the experimenter (unguided), ii) watching a video aiming to optimize participants' expectations before undergoing a single PMR session with the personal support of the experimenter (guided), iii) watching a neutral video (not aiming to optimize participants' expectations) before undergoing a single PMR session without personal support of the experimenter (unguided), or iv) watching a neutral video (not aiming to optimize participants' expectations) before undergoing a single PMR session with the personal support of the experimenter (guided). In a pre-posttest design, the subjective stress levels of the participants in the for groups will be analyzed.
This study aims to determine whether a brief video aiming to optimize expectations regarding the effectiveness of progressive muscle relaxation (PMR) can enhance the efficacy of a PMR compared to a neutral video control group in an online intervention. Another aim is to assess whether this effect will be moderated by the degree of human support (guided or unguided intervention).