The Impact of different Standing positions on Pelvic Muscle Activation and Lumbar Lordosis in LBP-developers during prolonged standing 

Abstract

Low back pain (LBP) development has been associated with increased hip muscle co-activation and lumbar lordosis during standing in previously asymptomatic individuals. It is commonly advised to use footrests to relieve LB. The impact of adjusting arm position on lumbar biomechanics can also be impressive. This study aimed to compare the effects of normalized footrest height and changing arm position on muscle activity, lumbar lordosis, and pain intensity. Twenty-four female pain developers (PDs) were recruited, identified by a > 10 mm increase on the visual analog scale (VAS) during prolonged standing. Electromyography (EMG) recorded hip muscle activity, and photogrammetry measured lumbar lordosis during one hour of standing. The first group used the footrest intermittently, while the second group additionally changed their arm positions. Both groups showed decreased gluteus medius co-activation during prolonged standing (p = 0.003), with the second group showing lower levels. A significant time effect on lumbar lordosis angle was observed in both groups (p < 0.01). Although lumbar discomfort increased over time and stepping interventions reduced this discomfort, with the second group reporting lower pain intensity (p < 0.05). Applying these interventions in the workplace could be beneficial to reduce discomfort for individuals who stand for long periods of time. Further research is needed to optimize these strategies and assess long-term benefits.