Abstract

The need for adjustability in school furniture, in order to accommodate the variation in anthropometric measures of different genders, cultures and ages is becoming increasingly important. Four chair-table combinations, different in dimensions, with adjustable chair seating heights and table heights were designed, manufactured and distributed to schools in Riyadh city. The number of the student participants was 28 (6 to <9 years), 30 (9 to <12 years), 30 (12 to <15 years) and 30 (≥ 15 years) in first, second, third and fourth age-group sets respectively. Muscular activity signals (EMGs) for both neck dorsal muscles and upper trapezius muscles, posture measures in terms of neck angle, viewing angle, back angle and discomfort ratings were considered as dependent factors. New designed adjustable sets versus current sets available in the schools were the independent variables. The results indicated that EMGs signals for both neck dorsal and upper trapezius muscles in the new sets were significantly lower when compared to the current sets. The three posture measures associated with the new sets were significantly improved when compared to the current sets. Finally, the participants' ratings of discomfort were significantly low for sitting on the new sets compared to sitting on the current sets.

Key words: School furniture, adjustable seat, EMG, discomfort rating, anthropometry