Estimation of compression load on L4/L5 based on electromyography technique in construction workers

Back pain among construction workers has a high prevalence compared to other jobs. Based on qualitative studies, numerous risk factors are involved in the development of back pain. The present study was conducted to evaluate prevalence of musculoskeletal disorders and the compressions loads on back based on surface electromyography in construction workers.

This study was conducted on 30 workers of various professions of building construction (rod busters, mason, stonemason, and manual material handling workers) in ahvaz city, Iran. In order to estimate the compression loads on the back, the surface electromyography technique was used, processing signals were determined using MATLAB software and analysis and interpretation of data were determined based on amplitude probability distribution function. The covariance analysis test was used to compare the compressive loads on the low back (L4/L5) as well as the exposure time between different occupational groups.

The highest and lowest mean of compression pressure (50th percentile) was estimated among the manual material handling workers and masons, respectively.There was a significant difference between the compressive loads on the back among different occupational groups(p <0.05).Stonemasonry workers and manual material handling workers bear more than 3400 N compression load in their low back between 25% and 30% of the exposure time. Stonemasonry workers and manual material handling workers had significantly more exposure time to compression loads over 3400 N, compared to the armature assemblers (p <0.05).

The biomechanical evaluation results of this study showed that the compression load on the back of the workers in various construction jobs was high, especially among manual material handling workers and in comparison with the threshold limit, some jobs are in exposure to many risk factors due to their nature. In general, according to the findings, it seems that with the implementation of administrative (reducing the work time and rotate the tasks of lifting and carrying) and engineering controls (use of proper mechanical devices and maintenance of transport equipment), the risk factors contributing to the development of back disorders can be controlled.