BACKGROUND: Work-related Upper Extremity Disorders (WRUEDs) are conceived of as a multifactorial syndrome caused by the effects of excessive repetitive motions, sustained static postures, and muscular stiffness. Our aim is to test an etiological model derived from a theory by Van Galen and Van Huygevoort [2000] Biol Psychol 51:151-171. The theory holds that physical, emotional, and psychosocial stressors enhance muscular stiffness as a compensatory filtering of impoverished signal-to-noise ratios in the motor system. High individual levels of arousal, as measured by Spielberger et al. [1970], State and Trait Anxiety Test would further enhance a subject's predisposition to react with stiffness responses in conditions of stress. METHODS: Ten participants with a high- and 10 with a low trait-anxiety score performed a computer task involving series of fast but well-dosed accelerations of the forearm along the surface of a digitizer. To induce cognitive stress a tone had to be remembered simultaneously with the aiming task. Pen-tip displacements and surface electromyographic (EMG) signals were recorded from four forearm muscles. RESULTS: Memory load did not affect error rates but produced shorter reaction times and prolonged movement times. EMG data show that under stress overall levels of neuromotor activation were enhanced. High-anxious participants exhibited higher cocontraction levels than low-anxious participants. CONCLUSIONS: The findings support the view that stress and muscular tension are closely related and may provide a clue to the origin of WRUEDs.
BACKGROUND: Work-related Upper Extremity Disorders (WRUEDs) are conceived of as a multifactorial syndrome caused by the effects of excessive repetitive motions, sustained static postures, and muscular stiffness. Our aim is to test an etiological model derived from a theory by Van Galen and Van Huygevoort [2000] Biol Psychol 51:151-171. The theory holds that physical, emotional, and psychosocial stressors enhance muscular stiffness as a compensatory filtering of impoverished signal-to-noise ratios in the motor system. High individual levels of arousal, as measured by Spielberger et al. [1970], State and Trait Anxiety Test would further enhance a subject's predisposition to react with stiffness responses in conditions of stress. METHODS: Ten participants with a high- and 10 with a low trait-anxiety score performed a computer task involving series of fast but well-dosed accelerations of the forearm along the surface of a digitizer. To induce cognitive stress a tone had to be remembered simultaneously with the aiming task. Pen-tip displacements and surface electromyographic (EMG) signals were recorded from four forearm muscles. RESULTS: Memory load did not affect error rates but produced shorter reaction times and prolonged movement times. EMG data show that under stress overall levels of neuromotor activation were enhanced. High-anxious participants exhibited higher cocontraction levels than low-anxious participants. CONCLUSIONS: The findings support the view that stress and muscular tension are closely related and may provide a clue to the origin of WRUEDs.
Authors: Maaike A Huysmans; Stefan Ijmker; Birgitte M Blatter; Dirk L Knol; Willem van Mechelen; Paulien M Bongers; Allard J van der Beek Journal: Int Arch Occup Environ Health Date: 2011-10-29 Impact factor: 3.015
Authors: David I Douphrate; Nathan B Fethke; Matthew W Nonnenmann; Anabel Rodriguez; Robert Hagevoort; David Gimeno Ruiz de Porras Journal: Ergonomics Date: 2016-12-23 Impact factor: 2.778