Muscle activity, time to fatigue, and maximum task duration at different levels of production standard time

[Purpose] This study investigated the variations in muscle fatigue, time to fatigue, and maximum task duration at different levels of production standard time. [Methods] Twenty subjects performed repetitive tasks at three different levels of production standard time corresponding to “normal”, “hard” and “very hard”. Surface electromyography was used to measure the muscle activity. [Results] The results showed that muscle activity was significantly affected by the production standard time level. Muscle activity increased twice in percentage as the production standard time shifted from hard to very hard (6.9% vs. 12.9%). The muscle activity increased over time, indicating muscle fatigue. The muscle fatigue rate increased for the harder production standard time (Hard: 0.105; Very hard: 0.115), which indicated the associated higher risk of work-related musculoskeletal disorders. Muscle fatigue was also found to occur earlier for hard and very hard production standard times. [Conclusion] It is recommended that the maximum task duration should not exceed 5.6, 2.9, and 2.2 hours for normal, hard, and very hard production standard times, respectively, in order to maintain work performance and minimize the risk of work-related musculoskeletal disorders.

[1]  M. Bryce Muscles Alive: Their Functions Revealed by Electromyography , 1963 .

[2]  J. Basmajian Muscles Alive—their functions revealed by electromyography , 1963 .

[3]  W Rohmert,et al.  Problems in determining rest allowances Part 1: use of modern methods to evaluate stress and strain in static muscular work. , 1973, Applied ergonomics.

[4]  H. M. Russell,et al.  Muscles Alive: Their Functions Revealed by Electromyography 3rd ed , 1974 .

[5]  T J Armstrong,et al.  Hand wrist cumulative trauma disorders in industry. , 1986, British journal of industrial medicine.

[6]  Vern Putz-Anderson,et al.  Cumulative trauma disorders : a manual for musculoskeletal diseases of the upper limbs , 1988 .

[7]  M Hagberg,et al.  Electromyographic signs of shoulder muscle fatigue in repetitive arm work paced by the Methods-Time Measurement system. , 1992, Scandinavian journal of work, environment & health.

[8]  S E Mathiassen,et al.  Physiological comparison of three interventions in light assembly work: reduced work pace, increased break allowance and shortened working days , 1996, International archives of occupational and environmental health.

[9]  Leonard O'Sullivan,et al.  Effects of gender and reach distance on risks of musculoskeletal injuries in an assembly task , 2002 .

[10]  Svend Erik Mathiassen,et al.  A case study evaluating the ergonomic and productivity impacts of partial automation strategies in the electronics industry , 2002 .

[11]  J. C. Cnockaert,et al.  Work-related musculoskeletal disorders of the upper limb. , 2002, Joint, bone, spine : revue du rhumatisme.

[12]  Hal W Hendrick,et al.  Determining the cost-benefits of ergonomics projects and factors that lead to their success. , 2003, Applied ergonomics.

[13]  L. Punnett,et al.  Work-related musculoskeletal disorders: the epidemiologic evidence and the debate. , 2004, Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology.

[14]  Guruprasad Madhavan,et al.  Electromyography: Physiology, Engineering and Non-Invasive Applications , 2005, Annals of Biomedical Engineering.

[15]  B. Koes,et al.  Repetitive strain injury , 1987, The Lancet.

[16]  M. Ferdjallah,et al.  Muscle fatigue analysis in young adults at different MVC levels using EMG metrics , 2007, Proceedings 2007 IEEE SoutheastCon.

[17]  Jung-Yong Kim,et al.  Measurement of trunk muscle fatigue during dynamic lifting and lowering as recovery time changes , 2007 .

[18]  R. Barredo,et al.  The Effects of Exercise and Rest Breaks on Musculoskeletal Discomfort during Computer Tasks: An Evidence-Based Perspective , 2007 .

[19]  Tsugutake Sadoyama,et al.  Electromyogram and perceived fatigue changes in the trapezius muscle during typewriting and recovery , 2007, European Journal of Applied Physiology.

[20]  Anne Moore,et al.  Quantifying precision and speed effects on muscle loading and rest in an occupational hand transfer task , 2007 .

[21]  D. Allen,et al.  Skeletal muscle fatigue: cellular mechanisms. , 2008, Physiological reviews.

[22]  Fouad Bennis,et al.  Dynamic Muscle Fatigue Evaluation in Virtual Working Environment , 2009, ArXiv.

[23]  Svend Erik Mathiassen,et al.  Increased physical work loads in modern work – a necessity for better health and performance? , 2009, Ergonomics.

[24]  Ritva Ketola,et al.  Effectiveness of an ergonomic intervention on the productivity of workers with upper-extremity disorders--a randomized controlled trial. , 2010, Scandinavian journal of work, environment & health.

[25]  T. Bosch,et al.  The effect of work pace on workload, motor variability and fatigue during simulated light assembly work , 2011, Ergonomics.

[26]  Joan M. Stevenson,et al.  The impact of an increase in work rate on task demands for a simulated industrial hand tool assembly task , 2012 .

[27]  Jeonghan Ko,et al.  Design of assembly lines with the concurrent consideration of productivity and upper extremity musculoskeletal disorders using linear models , 2012, Comput. Ind. Eng..

[28]  C. Chang,et al.  Understanding the link between psychosocial work stressors and work-related musculoskeletal complaints. , 2012, Applied ergonomics.

[29]  Aoife Finneran,et al.  Effects of grip type and wrist posture on forearm EMG activity, endurance time and movement accuracy , 2013 .

[30]  T. Imaeda,et al.  Work-related musculoskeletal disorders in the upper extremity among the staff of a Japanese university hospital , 2014, International Archives of Occupational and Environmental Health.

[31]  Suresh Rangan,et al.  Quantifying fatigue risk in model-based fatigue risk management. , 2013, Aviation, space, and environmental medicine.

[32]  Ju Sang Lee,et al.  Work-related Musculoskeletal Disorders among Korean Physical Therapists , 2013 .

[33]  Hyo-Lyun Roh,et al.  Analysis of Risk Factors for Work-related Musculoskeletal Disorders in Radiological Technologists , 2014, Journal of physical therapy science.

[34]  Jae-Hwan Cho,et al.  Factors Affecting the Musculoskeletal Symptoms of Korean Police Officers , 2014, Journal of physical therapy science.

[35]  Fouad Bennis,et al.  A new simple dynamic muscle fatigue model and its validation , 2022, ArXiv.