Psychophysically determined work-cycle parameters for repetitive hand gripping

International Journal of Industrial Ergonomics

2010

Section: Duty Cycle Timementioning

confidence: 99%

Force, posture and repetition induced discomfort as a mediator in self-paced cycle time

International Journal of Industrial Ergonomics

2010

“…Moore and Wells (2005) and Mathiassen and Winkel (1992) expressed concerns about using models such as the rest‐allowance model of Rohmert (1973) in the design of short‐cycle jobs, as the science behind the models were primarily based on endurance data from static exertions. Abu‐Ali, Purswell, and Schlegel (1996) investigated the effects of physical risk factors on self‐selected duty times, a measure of productivity. They developed a predictive model for duty time, but it was limited to forces in the range of 25–50% maximum voluntary contraction (MVC) and to times between 1 and 5 seconds.…”

Section: Introductionmentioning

confidence: 99%

The effects of force and exertion duration on duty cycle time: Implications for productivity

2010

Hum Ftrs & Erg Mfg Svc

Ergonomics has positive effects on both physical health and productivity, but estimating productivity benefits is difficult at the task design/redesign stage. Rest allowance prediction models are not suitable for repetitive short cycle dynamic tasks and MTM techniques are limited in their suitability for considering ergonomics risk factors such as posture and force. The purpose of this study was to investigate the relationship between force and exertion duration on self selected duty cycle time and discomfort. Twenty one participants completed repetitive upper limb exertion treatments, each of duration ten minutes. Five levels of Force (10, 20, 40, 65 and 80% MVC) and Exertion period (1, 2, 4, 6.5 and 8 seconds) were investigated. The psychophysical adjustment method was used whereby participants self selected a work pace for the second half of each treatment. Duty cycle, derived from the self pace cycle time, was the measure of productivity effects in the experiment. ANOVA revealed a significant effect on duty cycle time for force, exertion period and the interaction (each p<0.0001). Friedmans test indicated a significant effect of force (p<0.0001) and exertion period (p<0.0001) on discomfort. Spearman's correlation analysis showed a strong correlation between discomfort and duty cycle time (p<0.05). Multiple regression analysis was used to develop a predictive model for duty cycle time based on force and exertion period, and this was a good fit to the data (R 2 = 0.98, p<0.05). Profiles were generated presenting zones of acceptable self selected duty cycle times based on force and exertion duration.

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“…Initial cycle time was set at 5 seconds so that DCT would be 40%. Models developed by Finneran and O'Sullivan (2010b) and Abu-ali et al (1996) found that in high force conditions average maximum DCT was approximately 40%.…”

Section: Experiments Designmentioning

confidence: 99%

“…the active time within a work cycle) was calculated from Self-Paced Cycle Time and exertion period based on definitions and work by Moore and Wells (2005), Abu-Ali et al (1996) and Finneran andO'Sullivan (2010a and2010b). Discomfort was measured once per minute over the 25 minute testing combination using a 100 mm Visual Analogue Scale (VAS).…”

Section: Psychophysical Approachmentioning

confidence: 99%

“…However, organisational pressures to increase output can result in increased mental and physical stress for the operator (De Looze et al, 2003). For example, when rest breaks are insufficient or poorly planned (Abu-Ali et al, 1996), or when tasks are poorly designed (Fagarasanu and Kumar, 2003), labour productivity is directly impacted. Actual productivity effects in relation to operator health may be expressed in terms of absenteeism and presenteeism.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Self-selected duty cycle times for grip force, wrist flexion postures and three grip types

2014

Ergonomics