The effect of rest break schedule on acute low back pain development in pain and non-pain developers during seated work.

A significant portion of the population (25-50%) is known to develop acute low back pain (LBP) within a bout of prolonged sitting. Previous research has supported the use of frequent rest breaks, from seated office work, in order to reduce self-reported LBP, however, there is limited consensus about the recommended frequency and duration of rest breaks. This may be due to the limited consideration of individual differences in acute LBP development. The purpose of this study was to examine the effect of three different standing rest-break conditions on a group of pain developers (PD) and non-pain developers (NPD) engaged in prolonged seated work. Twenty participants completed four one-hour-long bouts of seated typing: Condition A - no rest; Condition B - 5 min of standing rest every 30 min; Condition C - 2.5 min of standing rest every 15 min; Condition D - 50 s of standing rest every 5 min. Self-reported LBP, self-reported mental fatigue and 30-s samples of EMG were collected every 10 min throughout each session. Eight out of 20 participants (40%) reported LBP during Condition A (classified as PD). Only PD demonstrated clinically relevant increases in LBP across conditions where Conditions B, C, or D provided some relief, but did not restore pain scores to their original level, prior to sitting. PD and NPD developed mental fatigue equally, with Conditions B and D helping to reduce fatigue. No differences in productivity were observed between conditions or groups and no main effects were observed for muscle activity, median power frequency or co-contraction. These data suggests that frequent, short, standing rest breaks may help to reduce symptoms of LBP, however they are only a temporary solution as PD still developed clinically important LBP, even with frequent rest breaks.