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

Finneran, Aoife; O’Sullivan, Leonard

doi:10.1016/j.ergon.2010.01.004

Cited by 31 publications

(26 citation statements)

References 41 publications

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“…Finneran & O'Sullivan (2010) investigated the effects of force and exertion duration on duty cycle and found that a task with a high level of force resulted in a higher level of discomfort and a decrease in the self-paced duty cycle, meaning that when a participant performs a task requiring much force, a longer recovery time is needed, hence the decrease in duty cycle.…”

Section: Effects Of Force Level Variations On Fatigue Developmentmentioning

confidence: 99%

“…Researchers such as Iridiastadi & Nussbaum (2006), Dickerson et al (2015), and Rashedi & Nussbaum (2016) claim that shorter cycle times could be linked to a slower development of muscle fatigue as shorter cycle times tended to have "positive physiological effects", although the latent benefits of varying cycle times across a range of tasks still had to be defined (Iridiastadi & Nussbaum, 2006). Finneran & O'Sullivan (2010), on the other hand, believe that longer cycle times that include varieties of subtasks (e.g., with varying force variations and duty cycles) may be more beneficial than short cycle times, as highly repetitive tasks can lead to increased pressure on the peripheral nerves. This leads to swelling (Forde et al, 2002;Punnett & Wegman, 2004), which in turn will affect blood flow to the working muscles, resulting in localized fatigue.…”

Section: Cycle Timementioning

confidence: 99%

“…Cycle time is the total time from the beginning to the end of one process (Seghers & Spaepen, 2004), thus allowing one cycle of activation and rest phase to be completed before being repeated (Finneran & O'Sullivan, 2010). Within a single cycle, the duty cycle determines the duration of the muscle activation; in other words, the proportion of time an individual is engaged in the frequency of the task (Potvin, 2012).…”

Section: Cycle Timementioning

confidence: 99%

“…The 10-second cycle time was chosen due to the amount of literature that has used a cycle time of ten seconds as a variable of no interest (Björkstén, & Jonsson 1977;Vollestad et al, 1997;Finneran, & O'Sullivan;2010;Green et al, 2015). A 5-second cycle time was chosen as half of the 10-second cycle to replicate short and highly repetitive actions.…”

Section: Cycle Timementioning

confidence: 99%

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An Exploration of the Effects of Cycle Time and Force Variations on Muscle Fatigue during Submaximal Intermittent Isometric Exertions

King¹,

Mattison²

2017

Ergonomics South Afr

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This study investigated the effects of two intermittent task parameters on muscle fatigue, namely cycle time and force level variation. Of particular interest was whether a constant low-level underlying force would contribute to fatigue. Twelve students participated in four experimental conditions, each lasting 8 minutes. Participants repeatedly performed intermittent isometric exertions of biceps brachii at two cycle times (5 or 10 seconds), and two force levels, varying either between 0% and 50%max isometric force or between 10% and 40%max force. These parameters and a duty cycle of 0.5 ensured a mean force exertion of 25%max for all conditions. Muscle fatigue was inferred from local Ratings of Perceived Exertion (RPE), maximum force and EMG(RMS). Significant (p<0.05) increases in RPE and EMG(RMS), and reductions in maximum force overtime indicate fatigue development during all conditions. Conditions with force levels varying between 10% and 40%max force showed significantly greater RPE and EMG(RMS) recordings, but only marginal reductions in maximum force (p=0.350), compared to conditions with force varying between 0% and 50%max force. Cycle time did not significantly influence fatigue development since no significant changes occurred for RPE, maximum force or EMG(RMS). These results show accelerated fatigue development under conditions with a constant underlying force, despite the lower maximum exertion level, and irrespective of cycle time. Work involving intermittent static force exertions should thus include periods of complete relaxation between exertions to prevent the early onset of muscle fatigue.

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Section: Effects Of Force Level Variations On Fatigue Developmentmentioning

confidence: 99%

Section: Cycle Timementioning

confidence: 99%

Section: Cycle Timementioning

confidence: 99%

Section: Cycle Timementioning

confidence: 99%

See 2 more Smart Citations

An Exploration of the Effects of Cycle Time and Force Variations on Muscle Fatigue during Submaximal Intermittent Isometric Exertions

King¹,

Mattison²

2017

Ergonomics South Afr

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show abstract

“…Many studies have been carried out on the evaluation of upper-limb repetitive tasks (Kilbom, 1994), and many of them were based on psychophysical approaches (Mukhopadhyay et al, 2007;Finneran and O'Sullivan, 2010;Lin et al, 2010). The psychophysical study on the basis of perceived discomfort has the economic merit as compared to the physiological or biomechanical methods that require relatively high-priced equipment and it has been acknowledged as a systematic workload evaluation methodology based on psychophysics.…”

Section: Introductionmentioning

confidence: 99%

Relationship of EMG and Subjective Discomfort Ratings for Repetitive Handling of Lightweight Loads

Lee

Jo²

2014

Journal of the Ergonomics Society of Korea

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

Finneran

O’Sullivan

2010

Hum Ftrs & Erg Mfg Svc

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

Cited by 31 publications

References 41 publications

An Exploration of the Effects of Cycle Time and Force Variations on Muscle Fatigue during Submaximal Intermittent Isometric Exertions

An Exploration of the Effects of Cycle Time and Force Variations on Muscle Fatigue during Submaximal Intermittent Isometric Exertions

Relationship of EMG and Subjective Discomfort Ratings for Repetitive Handling of Lightweight Loads

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

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