Lean Production and Its Impact on Worker Health: Force and Fatigue-Based Evaluation Approaches

Introduction

In today's global competition, successful companies focus on diversity and inclusion as a source of competitive advantage. The organizations use diverse methods and techniques to improve their productivity, quality, and profitability. In order to achieve this, the work organization system of lean production has been widely adopted throughout the industrial world. Lean originates from the Toyota Production System and has been recognized as doing more with less. Thus, it is oriented toward reduction of unnecessary variations and steps in the work process by the elimination of waste, which can be thought of as a non-value-added aspect of a product or service. Originally, the focus was paid to the elimination of wastes such as defects requiring rework, unnecessary processing steps, movement of materials or people, waiting time, excess inventory, and overproduction. But today Lean systems impact a wide-range of manufacturing related systems including the initial stages of product life cycle such as product development, procurement and manufacturing over to distribution (Womack & Jones, 1996). The most common practices associated with lean production are the following: bottleneck removal (production smoothing), cellular manufacturing, competitive benchmarking, continuous improvement programs, cross-functional work force, cycle time reductions, focused factory production, just-in-time/continuous flow production, lot size reductions, maintenance optimization, new process equipment/technologies, planning and scheduling strategies, preventive maintenance, process capability measurements, pull system/Kanban, quality management programs, quick changeover techniques, reengineered production process, safety improvement programs, self-directed work teams, and total quality management (Shah & Ward, 2003).

It should be clearly pointed out that the misusage of lean techniques can lead to overlooking issues that lead to health problems, injuries, or even accidents. All these consequences lead to the need to spend money on compensation claims, which may be the best example of waste (Pai et. 2009). The awareness of the relationship between worker health and lean among lean practitioners is not always visible. There are some studies which show such an impact in the areas of occupational injuries and illnesses, or job characteristics related to job strain and linked to hypertension and cardiovascular disease (Landsbergis et al., 1999). Furthermore, it has been investigated that lean production can empower workers (Shah & Ward, 2003; Taj & Morosan, 2011) as it requires intensified work pace and increased job demands. Decision authority and skill levels can increase modestly or temporarily, while decision latitude is kept at low level which can lead to job strain and finally, musculoskeletal disorders. In jobs with ergonomic stressors, intensification of labor appears to lead to increases in musculoskeletal disorders (Landsbergis et al., 1999). Lean may result in raised stress levels and therefore increase worker turnover and absenteeism with a negative impact on manufacturing performance (Gill, 2003). However, further studies revealed that this approach in fact increases the stress levels. But not on the shop floor as it was previously suggested, but rather on the managerial level (Sangwan, 2013). Furthermore, when lean was tested against such work organization models as: Taylorism model, human relations model and socio-technology models, on the two dimensions central or decentralized orientation and human factor orientation; it turned out that it outperforms both the Taylorism model and the human relations model (European Foundation Report, 2001).