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MANUAL HANDLING & ERGONOMICS


TAKE STEPS TO REDUCE FATIGUE


In many industries, employees work while standing, walking and/or carrying loads. Experts agree that anti-fatigue matting can significantly improve


productivity and employee satisfaction while reducing absenteeism and chronic illnesses related to prolonged standing, Giselle Dirckx, Director of Marketing, Checkers Safety Group explains the findings.


Although the outcome of studies in favour of using mats is perfectly clear, the effectiveness remains subject to the perception of workers. Taking the existing matting research to the next level, Prof. Dr. Redha Taiar, an expert in biomechanics at the University of Reims in France, studied how the material and design of the mat affects the level of comfort especially for varying weights and comparing standing still for long periods to walking up and down. Using numerical modelling to illustrate how the force (weight) of the standing worker is distributed over the anti-fatigue mat, he was able to demonstrate how the weight distribution on the mat was influenced by such factors as the type of material, composition, density, surface pattern and the engineering of the product.


How an anti-fatigue mat works is well described in an article that was published in the April 1999 issue of “Occupational Health & Safety”, written by James M. Kendrick: “Anti- fatigue mats are engineered to make the body naturally and imperceptibly sway, which encourages subtle movement by calf and leg muscles. This promotes blood flow and keeps it from stagnating in the veins, which causes workers to feel fatigued.”


As noted by Mr. Kendrick, the cushioning effect of anti-fatigue matting allows continuous micro- movements of the feet, which minimizes blood pooling in the legs. There is good reason to believe that reduction of fatigue also reduces the possibility of accidents and improves general work efficiency. There are fewer days lost to injuries, fewer medical claims, and compliance with new health and safety requirements.


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In 2011, Prof. Dr. Redha Taiar’s research, Standing Smart, investigated the benefits of anti- fatigue matting in restoring the balance of the standing worker. Without mats, the results showed a dysfunctional balance. The distribution of foot pressure obtained (30% and 70% of the weight of the body) is mainly on the right side. This imbalance is very harmful for the human body. With mats in working situations where people make small movements constantly, the anti- fatigue mats corrected balance and ensured a uniform distribution between the right and left leg.


“REDUCTION OF


FATIGUE ALSO REDUCES THE POSSIBILITY OF ACCIDENTS AND


IMPROVES GENERAL WORK EFFICIENCY.”


Feedback from employees was also used to support the research using observations from workers who compared working on anti-fatigue mats to working on the hard floor and noting their level of comfort and fatigue every hour during eight-hour shifts. One worker commented: “Less fatigue in the legs at the end of the day and less muscular and articular troubles, better absorption of weight.” The feedback from workers on the best mat suited to their needs varied between the three test mats.


The physical size of the worker, and their own preferences as to what is comfortable, will cause different mats to be selected. A person weighing 90kg may prefer


a different mat than someone who only weighs 60kg.


The softness/hardness may also affect the worker’s freedom of movement. Think of it like jogging on the beach as an extreme example of this concept. Too much cushioning can have a negative effect. Too great an amount of softness or “give” will actually cause excessive fatigue because it overworks the muscles.


Prof. Dr. Redha Taiar expanded the research on anti-fatigue matting in 2015 by studying the reaction of the material and range of the displacement when subjected to weights varying from 50kg to 110kg using numerical modelling to compare and analyse the displacement and Von Mises stresses.


Models were developed using the Abaqus software. Numerical analysis was performed in two steps. The first step was to apply a 600N force normal to the surface on a 50x50mm area at the sample centre. Displacement and Von Mises stresses were analysed on each surface. The second step included the application of a force normal to the surface 500-700-900- 1100N (50kg to 110kg) magnitude. Displacement was analysed according to the applied load.


The reaction of the mat was influenced by such factors as the type of material, composition, density, the surface pattern and the engineering of the product.


The results showed the impact that the type of material and design has on the compression and dispersion of weight (energy). A higher dispersion of weight is better suited for static standing positions vs. a high potential stored energy or


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