The impact of a progressive sit-stand rotation exposure duration on low back posture, muscle activation, and pain...

This study evaluated early and frequent seated breaks from standing work to reduce low back pain (LBP) in known pain developers (PD). Twenty-four participants, classified as either PD or non-PD during a separate 2-hour standing session, performed 124 minutes of standing work with seated breaks at a 3:1 stand-sit ratio with increasing durations from 3:1 minute to 48:16 minutes. Back pain and spine posture measures showed no differences between PD and non-PD. Females had greater left glutaeus medius activation (8.4%MVC) than males (4.5%MVC) and greater glutaeus medius co-contraction. This protocol was successful at reducing LBP in PD to the level of non-PD, with mean pain scores (13 mm) only slightly exceeding the clinical LBP threshold of 10 mm. Early and frequent breaks within the first hour of standing work appear to be an effective solution to reduce the LBP that often occurs at the beginning of standing work. Practicioner Summary: Sit-stand workstations may be an effective solution to reduce static occupational low back postures. This experimental study demonstrated that early and frequent seated breaks from standing work may be an effective solution to reduce tissue aggravation that often occurs within the first 45 minutes of a standing work exposure. Abbreviations: LBP: low back pain; PD: pain developer; NPD: non-pain developer; VAS: visual analog scale; EMG: electromyography; LES: lumbar erector spinae; TES: thoracic erector spinae; GMD: glutaeus medius; IOB: internal oblique; MVC: maximum voluntary contraction; CCI: co-activation coefficient; FDA: functional data analysis.