Fatigue and recovery during and after static loading

Abstract

Subjectively assessed endurance time (ET), resumption time (RT) and perceived discomfort, pain or fatigue (PD), and objectively measured maximum force-exerting capacity were investigated for varying loads and durations of a pushing task with two repeated trials. Beyond the main results quantifying how the load scenario affected ET, RT and PD, three additional results are of note: (1) although the maximum pushing force did not change between trials, shorter ET, longer RT and higher PD indicated accumulation of fatigue in Trial 2; (2) the PD ratings showed a trend with a linear increase during loading and a curvilinear decrease during recovery; and (3) the RT and the load level for different relative loading times were found to have an unexpected U-shaped relationship, indicating lowest fatigue at the intermediate load level. These results can be used to model a more sustainable and productive work-recovery ratio.

Abstract

Practitioner Summary: Sufficient recovery during a work-shift is important for sustainable work. This paper presents data from an empirical study on how fatigue reactions and recovery needs vary with load level and loading time and with one repeated loading. The results enable the modelling of work-recovery ratios to ensure adequate recovery during work-shifts.

Keywords::

• resumption time
• perceived discomfort/pain/fatigue
• force
• subjective assessment

Acknowledgements

The authors thank the participants of this study and Professor Roland Örtengren at Chalmers University of Technology.

Additional information

Funding

Financial support from SBUF, the Swedish construction industry's organisation for research and development, from AFA Insurance and from the Natural Sciences and Engineering Research Council of Canada (NSERC) is gratefully acknowledged.