Following an initial questionnaire, student volunteers without a history of'serious" back pain were classified
as either postural backache group or no baekache group, Witb the use of an activity diary tbat plotted activity every
5 minutes over a 3-day period, the average time spent in different postures was established. Relaxed sitting posture was
evaluated using Dartfish software to analyze videotape after 10 minutes of sitting.