Lower Torso Muscle Activation Patterns for High-Magnitude Static Exertions: Gender Differences and the Effects of Twisting

Details

• Personal Author:
  Nussbaum MA ; Perez MA
• Description:
  Surface electromyographic signals were collected from 14 lower torso muscles while participants resisted high-magnitude static trunk moments applied in a variety of directions. To obtain a description of muscle activations in response to large moment magnitudes and axial twisting, including levels of agonistic and antagonistic muscle cocontraction. To assess differences in lower torso muscle activation patterns associated with gender and trial repetition. Back pain is associated with mechanical loads in the back. Biomechanical modeling of these loads is facilitated by knowledge of typical muscle activation patterns. Previous efforts in obtaining such data have often limited their scope to low-magnitude exertions or relatively simple scenarios. Eight male and eight female participants, matched by height and mass, performed static exertions in an apparatus that immobilized their lower body while the activation levels of seven bilateral torso muscles were measured using surface electromyography. Activation patterns were analyzed to assess differences resulting from a variety of factors. No significant differences in activation patterns were found between genders or repetitions, but moment magnitude and direction elicited substantial differential responses. Good repeatability was found between trial repetitions, as indicated by intraclass correlation coefficients (>0.65). Significant synergistic muscle coactivation, large intersubject variability (mean coefficient of variation 82.2%), and consistent levels of antagonism ranging from 10% to 30% maximum voluntary exertions were observed. Individuals of different genders, but similar anthropometry, have comparable muscular reactions to complex torso loads, suggesting similar motor control strategies. Future spine models should consider that the variability in muscle recruitment patterns is larger between subjects than within subjects. High-magnitude exertions, especially those with moment loads in more than one plane, require most muscles to be active (>5%) and moderate levels of antagonism. [Description provided by NIOSH]
• Subjects:
  Dust Engineering Mining Occupational Health Safety
• Keywords:
  Anthropometry Back-injuries Biomechanics Demographic-characteristics Injuries Muscle-contraction Muscle-tension Muscles Repetitive-work Sex-factors
• ISSN:
  0362-2436
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  27
• Issue:
  12
• NIOSHTIC Number:
  nn:20031285
• Citation:
  Spine 2002 Jun; 27(12):1326-1335
• Contact Point Address:
  Maury A. Nussbaum, PhD, Grado Department of Industrial & Systems Engineering, 250 Durham Hall (0118), Virginia Tech, Blacksburg, VA 24061
• Email:
  nussbaum@vt.edu
• Federal Fiscal Year:
  2002
• Performing Organization:
  Virginia Polytechnic Institute and State University, Blacksburg
• Peer Reviewed:
  False
• Start Date:
  20010701
• Source Full Name:
  Spine
• End Date:
  20260630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:7898622e050b8f5326ef2476ba3c8676ecaf536482ec7e1b0f9ce4e7ab139543a7ac6698b1530c5926c64caaabd137836808d204e84afe60e4314e81a60745b1
• Download URL:
  https://stacks.cdc.gov/view/cdc/191579/cdc_191579_DS1.pdf
• File Type:
  [PDF - 2.45 MB ]