2.3. Procedure 
trunk muscle fatigue
A screening process was used to determine participants’ eligibility for the study, and demographic data were recorded through direct interviews. Thirty healthy participants were asked to sign informed consent forms before participating. Participants who met the inclusion criteria were then asked to visit the research laboratory on three consecutive days and were randomly selected to sit in three positions, as shown in One researcher informed the participants throughout the study. Another researcher measured the outcomes, including trunk muscle fatigue, participant satisfaction, and discomfort scores. The assessment times for each outcome are shown in 