Effects of postural intervention using a <i>risshin</i> chair on physical posture, class time perception, and subjective well‐being in junior high school students

BACKGROUND: Research based on embodied cognition has demonstrated that physical posture, particularly an upright seated posture, can influence emotions and cognition. However, although students spend most of the day sitting in classrooms, intervention research on upright seated postures suitable for learning environments is limited. AIMS: We aimed to examine the effects of postural intervention via a 'Zazen-like upright-support seating furniture' (a risshin chair) on physical posture, class time perception, positive affect, and daily sense of fulfilment in school in a junior high school setting. SAMPLE: = 13.39 years, SD = .49) from two classes of a single grade at a public school in Japan. METHODS: Using a within-participants design, students alternated between sitting in regular and risshin chairs in an A-B-A-B-A order for approximately five weeks. At the end of each week, they completed a self-report questionnaire during the final homeroom session on every Friday. RESULTS: Bayesian linear mixed-effects modelling revealed significant effects of the risshin chair on posture-related outcomes, such as autonomous posture improvement, straight back, and tension release. Bayesian mediation analysis with linear mixed-effects modelling further showed that the risshin chair reduced time-related distracted thoughts, increased pleasantness, and enhanced daily school fulfilment, with these effects mediated via improved straight-back posture. CONCLUSIONS: Although short-term, the risshin chair improved specific aspects of students' physical posture, class time perception, and subjective well-being during school compared with regular chairs.