Arm positioning in manual tasks. An electromyographic study of localized muscle fatigue.

Myoelectric activity in four different shoulder muscles was collected and interpreted as indirect indicators of the load in eight different arm positions. The power spectrum changes associated with localized muscle fatigue were measured using a new dedicated instrument. Localized muscle fatigue was present in all muscles, in overhead and shoulder level work, and in some cases in waist level work • as well. For instance, in overhead work, the supraspinatus load was significantly affected by elbow positioning. The infraspinatus muscle held the highest fatigue effects of all muscles investigated. The results indicate the possibility of finding positions entailing reduction of the total muscular load in different working situations.

[1]  D. Chaffin.  Localized muscle fatigue--definiton and measurement. , 1973, Journal of occupational medicine. : official publication of the Industrial Medical Association.

[2]  Dynamic frequency analysis of myo-potentials. , 1968, Electroencephalography and clinical neurophysiology.

[3]  J A Anderson,et al.  Rheumatism in industry: a review , 1971, British journal of industrial medicine.

[4]  R. Kadefors,et al.  An electromyographic index for localized muscle fatigue. , 1977, Journal of applied physiology: respiratory, environmental and exercise physiology.

[5]  I Petersén,et al.  Dynamic spectrum analysis of myo-potentials and with special reference to muscle fatigue. , 1968, Electromyography.

[6]  C. J. De Duca,et al.  Force analysis of individual muscles acting simultaneously on the shoulder joint during isometric abduction. , 1973, Journal of biomechanics.

[7]  L. D. Haber.  Disabling effects of chronic disease and impairment. , 1971, Journal of chronic diseases.

[8]  G. Andersson,et al.  Low back pain in industry: epidemiological aspects. , 1979, Scandinavian journal of rehabilitation medicine.

[9]  D B Lucas,et al.  Biomechanics of the shoulder joint. , 1973, Archives of surgery.

[10]  I Petersén,et al.  Muscular reaction to welding work: an electromyographic investigation. , 1976, Ergonomics.

[11]  M Hagberg,et al.  Clinical and ergonomic factors in prolonged shoulder pain among industrial workers. , 1979, Scandinavian journal of work, environment & health.

[12]  B Jonsson,et al.  Displacement, deformation and fracture of wire electrodes for electromyography. , 1968, Electromyography.

[13]  J L Kelsey,et al.  The impact of musculoskeletal disorders on the population of the United States. , 1979, The Journal of bone and joint surgery. American volume.

[14]  E Allander,et al.  Prevalence, incidence, and remission rates of some common rheumatic diseases or syndromes. , 1974, Scandinavian journal of rheumatology.

[15]  R Kadefors,et al.  A study of painful shoulder in welders. , 1976, Acta orthopaedica Scandinavica.