The Importance of Lifting Height and Load Mass for Muscular Workload during Supermarket Stocking: Cross-Sectional Field Study

Abstract

High physical work demands increase the risk of musculoskeletal disorders and sickness absence. Supermarket work involves a high amount of manual material handling. Identifying specific ergonomic risk factors is an important part of occupational health and safety efforts in the supermarket sector. In this cross-sectional field study among 64 supermarket workers, we used electromyography during the workday to determine the influence of lifting height and load mass on muscular workload of the low-back and neck/shoulder muscles during un-restricted manual material handling (grocery stocking). We found a significant effect of load mass, i.e., higher loads associated with higher muscular workload in the low-back and neck/shoulder muscles. We demonstrated a significant interaction between start and end position, i.e., lifts performed from ‘Low’ start positions to ‘High’ end positions demonstrated the highest low-back muscular workload, whereas ‘High’ positions were associated with increased neck/shoulder workload. In conclusion, lifting higher loads and lifting goods from low to high positions (low-back) and at high positions (neck/shoulder) are associated with higher muscular workload. These results can be used to guide highly warranted preventive initiatives to reduce the physical workload during supermarket work.

Influence of brick laying height on biomechanical load in masons: Cross-sectional field study with technical measurements

“…Previous research manifested similar findings during a simulated drilling task [70] and among a convenience sample of supermarket workers [71,72]. Occupational lifting with arms above shoulder height resulted in higher muscular workload based on sEMG measurements and higher compression forces in the shoulder joints based on a musculoskeletal modelling approach [71,72]. The above mentioned findings elaborate on previous studies showing that elevated arm work increases the biomechanical load of the shoulder muscles and restricts the blood supply to shoulder and arm tissues [73].…”

“…The present study showed an even distribution on the physical workload between the dominant and non-dominant side (Table 2) as well as an increased physical workload on the neck/shoulder muscles when the bricklayers performed their work above shoulder height. Previous research manifested similar findings during a simulated drilling task [70] and among a convenience sample of supermarket workers [71,72]. Occupational lifting with arms above shoulder height resulted in higher muscular workload based on sEMG measurements and higher compression forces in the shoulder joints based on a musculoskeletal modelling approach [71,72].…”