Easier than standing all the time!? What is the possibility of reducing fatigue through dynamic standing?!

Fatigue problems in standing jobs

Manufacturing and assembly workers are often forced to stand all day, which increases the risk of musculoskeletal disorders (MSDs). In particular, stationary standing posture can reduce blood flow and cause muscle fatigue, leading to back and leg pain. In this article, we explore whether dynamic standing posture can reduce fatigue and improve work efficiency.

Research summary: Comparison of dynamic and static standing positions

A study conducted by a research group at the Indian Institute of Technology, Madras (Balasubramanian et al., 2009) evaluated the effects of dynamic and static standing on muscle fatigue during assembly tasks. In this study, nine subjects:

• Static standing: Stay in one place and keep working
• Dynamic standing: Assembly work was performed under two conditions: one where the worker moves between multiple work tables, and the other where the worker moves between multiple work tables. The fatigue level for each condition was evaluated.

Evaluation method

1. Electromyogram (sEMG) measurement : Quantifying the progression of muscle fatigue
2. Psychophysical analysis : subjective assessment of pain and discomfort after the task

Muscle measurement sites used in the experiment (Figure 1)

In this study, we measured sEMG data from the following four muscles:

• Left Gastrocnemius (LG)
• Right gastrocnemius (RG)
• Right Trapezius (RT)
• Right Erector Spinae (RES)

These are the muscle groups that are most heavily loaded when working while standing, and are areas where fatigue accumulation is a problem.

Research results: Effectiveness of dynamic standing

1. Measurement results using electromyogram (sEMG) (Figure 3)

• In static standing , muscle fatigue in the legs and lower back was significantly higher (p < 0.05).
• Dynamic standing slows down the progression of muscle fatigue and reduces strain on the muscles, especially in the lower back and calf.

Key points in Figure 3

• (A) RMS slope : When standing statically, the RMS value rises sharply, and muscle fatigue progresses.
• (B) Slope of MPF : During static standing, MPF decreases rapidly, indicating a decrease in muscle endurance.

2. Subjective evaluation (psychophysical analysis)

• Static standing was associated with more leg and shoulder pain (p < 0.05) and increased overall discomfort
• Dynamic standing reduces fatigue and improves comfort

Key points in Table 1

• In static standing, pain scores in the legs, shoulders, and lower back were high.
• Dynamic standing resulted in less pain and greater comfort overall.

Why is dynamic standing effective?

In static standing, maintaining the same posture for a long period of time reduces blood flow and causes muscles to become oxygen deprived. On the other hand, in dynamic standing, walking promotes blood circulation and improves oxygen supply to muscles, preventing fatigue accumulation.

Research suggests that simply incorporating two to four minutes of walking every 15 minutes can reduce venous pressure in the legs and reduce feelings of fatigue (Konz & Johnson, 2000).

How to implement it in the workplace

1. Improved work area design (Fig. 2)

• Multiple work stations have been set up to create an environment where employees can move around naturally
• Incorporating dynamic movements into assembly lines reduces muscle fatigue

Key points in Figure 2

• Six work tables are set up and workers can move around while working.
• Moving around promotes blood flow to the muscles and prevents fatigue from building up.

2. Introduction of appropriate footwear and mats

• Use highly cushioned shoes and a standing work mat
• Reduces strain on your feet even when working in a standing position for long periods of time

3. Education and enlightenment for workers

• Understand the importance of dynamic standing and teach proper posture
• Regular breaks and simple stretches are recommended

summary

This study showed that dynamic standing slows the progression of muscle fatigue and improves worker comfort compared to static standing . In manufacturing and assembly work, adopting a work style that involves walking may contribute to reducing fatigue and improving productivity .

References

• Balasubramanian, V., Adalarasu, K., & Regulapati, R. (2009). Comparing dynamic and stationary standing postures in an assembly task. International Journal of Industrial Ergonomics , 39(5), 649-654.
• Konz, S., & Johnson, S. (2000). Work design: Occupational ergonomics. Holcomb Hathaway Publishing .