title: [A field study on the work load and muscle fatigue at neck-shoulder in female sewing machine operators by using surface electromyography].
abstract: OBJECTIVE
  To study neck and shoulder work-related muscle fatigue of female sewing machine operators.
  
  
  METHODS
  18 health female sewing machine operators without musculoskeletal disorders work in Beijing garment industry factory as volunteers in participate of this study. The maximal voluntary contraction (MVC) and 20% MVC of bilateral upper trapezium and cervical erectors spinae was tested before sewing operations, then the whole 20 time windows (1 time window = 10 min) sewing machine operations was monitored and the surface electromyography (sEMG) signals simultaneously was recorded after monitoring the 20%MVC was tested. Use amplitude analysis method to reduction recorded EMG signals.
  
  
  RESULTS
  During work, the median load for the left cervical erector spinae (LCES), right cervical erector spinae (RCES), left upper trapezium (LUT) and right upper trapezium (RUT) respectively was 6.78 ± 1.05, 6.94 ± 1.12, 5.68 ± 2.56 and 6.47 ± 3.22, work load of right is higher than the left; static load analysis indicated the value of RMS(20%MVC) before work was higher than that value after work, the increase of right CES and UT RMS(20%MVC) was more; the largest 20%MVE of bilateral CES occurred at 20th time window, and that of bilateral UT happened at 16th.
  
  
  CONCLUSIONS
  The work load of female sewing machine operators is sustained "static" load, and work load of right neck-shoulder is higher than left, right neck-shoulder muscle is more fatigable and much serious once fatigued.
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Peking University, Beijing 100191, China.
authors.forename: Fei-ruo
authors.initials: FR
authors.lastname: Zhang
authors.forename: Sheng
authors.initials: S
authors.lastname: Wang
authors.forename: Li-hua
authors.initials: LH
authors.lastname: He
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Shan-shan
authors.initials: SS
authors.lastname: Wu
authors.forename: Jing-yun
authors.initials: JY
authors.lastname: Li
authors.forename: Guang-yi
authors.initials: GY
authors.lastname: Hu
authors.forename: Kang-ping
authors.initials: KP
authors.lastname: Ye
mesh_terms: D000328:Adult; D004576:Electromyography; D005260:Female; D006801:Humans; D018763:Muscle Fatigue / Q000502:physiology*; D011187:Posture; D012782:Shoulder / Q000502:physiology*; D013783:Textile Industry; D014937:Work; D055815:Young Adult