Electromyographic mapping of the erector spinae muscle with varying load and during sustained contraction

K Tucker, Deborah Falla, T Graven-Nielsen, D Farina

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)


The purpose of the study was to explore changes in the spatial distribution of erector spinae electromyography amplitude during static, sustained contractions and during contractions of increasing load. Surface electromyographic (EMG) signals were detected from nine healthy subjects using a grid of 13 x 5 electrodes placed unilaterally over the lumbar erector spinae musculature. Subjects stood in a 20 degrees forward flexed position and performed: (1) six 20-s long contractions with loads ranging from 2.5 kg to 12.5 kg (2.5 kg increments) and (2) a 6 min sustained contraction with 7.5 kg load. Root mean square (RMS) and mean power spectral frequency (MNF) were computed from the recorded EMG signals. EMG RMS increased (P<0.0001) and MNF remained constant during contractions of increased load. During the sustained contraction, MNF decreased (P<0.0001) and RMS did not change over time. The centroid (center of activity) of the RMS map shifted caudally (P<0.0001) with time during the sustained contraction but did not change with varying load. These results suggest a change in the distribution of erector spinae muscle activity with fatigue and a uniform distribution of muscle activation across loads.

Original languageEnglish
Pages (from-to)373-9
Number of pages7
JournalJournal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology
Issue number3
Publication statusPublished - Jun 2009


  • Adult
  • Back
  • Electromyography
  • Humans
  • Lumbar Vertebrae
  • Male
  • Muscle Contraction
  • Muscle, Skeletal
  • Physical Exertion
  • Weight-Bearing
  • Journal Article
  • Research Support, Non-U.S. Gov't


Dive into the research topics of 'Electromyographic mapping of the erector spinae muscle with varying load and during sustained contraction'. Together they form a unique fingerprint.

Cite this