Standing work and low back pain: An experimental analysis of risk factors

Abstract

Background

Standing work is common across a wide range of industries and service sectors and has been associated with the development of low back pain.

Objective

To analyze changes in low back pain across eight experimental scenarios combining exposure to risk factors associated with standing work.

Methodology

A controlled factorial experiment (2³) comprising eight experimental scenarios and 32 simulations. Thirty volunteers (16 men and 14 women) participated in the study. Each participant completed an experimental scenario involving light manual activity in a standing position for 120 min, varying posture (dynamic or static), surface (hard or soft), and the use of insoles (with or without inserts). Every 30 min, low back pain intensity was recorded using a Visual Analog Scale (0 mm = no pain; 100 mm = maximum pain). Results: Time had a significant effect on increases in low back pain relative to baseline (T0 = 1.71, SE = 0.34). The estimated increases in low back pain from baseline were 1.41 at (T1), 2.38 at (T2), 3.07 at (T3), and 3.66 at (T4), all of which were statistically significant (p < 0.001).

Conclusions

Low back pain intensity increased significantly and similarly across all experimental scenarios, regardless of the combination of factors evaluated (posture, surface, or insole use). The results indicate that low back pain, as the starting point of clinical pain perception (≥ 9 mm VAS), manifests itself after 60 min of standing, regardless of the combined study factors.