The influence of lift frequency, lift duration and work experience on discomfort reporting

Changes in the amount and structure of motor variability during a deboning process are associated with work experience and neck–shoulder discomfort

“…Workers were divided in low/high experience groups if they had been performing the deboning task for less/more than one year as it has also been done in previous studies (Hakkanen et al, 2001;Parakkat et al, 2007). With respect to discomfort, we decided to limit ourselves to the neck-shoulder region due to the high prevalence of neck-shoulder pain in meat processing industry (ViikariJuntura et al, 1991;Frost et al, 1998).…”

“…This indicated that workers with discomfort operated in a posture where the head was either less flexed or shoulders were less elevated compared with the workers not reporting discomfort. Discomfort is also reported to influence the spinal load pattern during a lifting task (Parakkat et al, 2007). Further, muscle pain influences the neck and shoulder posture at work (Madeleine et al, 1999(Madeleine et al, , 2008a(Madeleine et al, , 2003bSzeto et al, 2002;Côté et al, 2005) even though some studies have reported no changes during work with lower physical demand (Birch et al, 2001;Arvidsson et al, 2008).…”

“…The low/high experience group consisted of workers with less/more than one year experience with deboning in accordance with previous studies (Hakkanen et al, 2001;Parakkat et al, 2007). Further, to analyze the relation between discomfort and kinematics data, subjects were divided into workers with and without discomfort in the neck-shoulder region ( Table 1).…”

“…A recent laboratory study by our group (Madeleine et al, 2008b) demonstrated that the size of cycle-to-cycle variability was larger among experienced butchers compared with novices and suggested that motor patterns change with learning and experience. Moreover, discomfort or pain has also been reported to change the size of motor variability (Parakkat et al, 2007;Madeleine et al, 2008a,b). Variability is a central characteristic of all human movement because of its role in motor learning and control (Latash and Anson, 2006).…”

Predicting subjective perceptions of powered tool torque reactions

“…Recently, Ku et al (2007) established an association between modeled powered hand tool kinetic exposures and actual upper limb injuries in an automobile assembly plant. Discomfort ratings of common manual materials handling tasks can also be affected by worker experience (Parakkat et al, 2007). Future studies are warranted to embrace the multi-faceted nature of powered tool use in order to develop a better understanding of their impacts for the tool users, and to establish an effective exposure limit guideline.…”