Standardized low-load repetitive work: evidence of different motor control strategies between experienced workers and a reference group.
The purpose of this laboratory study was to evaluate the possible differences in motor strategies to a new standardized low-load repetitive work task in between healthy experienced workers and a reference group. Work task event duration, i.e. working rhythm, cutting forces, surface electromyographic (EMG) activity from four shoulder muscles, postural activity, and arm and trunk movements in 3D were recorded during low-load repetitive work simulation. The experienced group showed lower EMG activity and frequency contents (P<0.05), more abducted position of the upper arm and forward flexion of the trunk prior to work simulation (P<0.05), and increased arm and trunk range of motion (P<0.05) compared with the reference group. The results highlight that experienced butchers have a different motor strategy compared with a reference group, i.e. more variable form of coordination pattern. Furthermore, the initial implementation of a possible protective motor strategy by experienced workers might be a very important prognostic factor.
Madeleine
Pascal
P
Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7, Building D-3, DK-9220 Aalborg, Denmark. pm@smi.auc.dk
Lundager
Birthe
B
Voigt
Michael
M
Arendt-Nielsen
Lars
L
D000328:Adult; D000704:Analysis of Variance; D001132:Arm / Q000502:physiology; D004576:Electromyography; D005511:Food Handling; D006801:Humans; D008297:Male; D008875:Middle Aged; D009048:Motor Skills; D009068:Movement; D009140:Musculoskeletal Diseases / Q000517:prevention & control*; D009784:Occupational Diseases / Q000517:prevention & control*; D011187:Posture; D016059:Range of Motion, Articular; D012785:Shoulder Joint / Q000502:physiology; D013647:Task Performance and Analysis