Affiliations: [a] Department of Health and Exercise Science, University
of Oklahoma, Norman, OK, USA
Note: [] Address for correspondence: Travis W. Beck, Ph.D., University of
Oklahoma, Department of Health and Exercise Science, 110 Huston Huffman Center,
Norman, OK 73019-6081, USA. Tel.: +1 405 325 1378; Fax: +1 405 325 0522; E-mail: tbeck@ou.edu
Abstract: The purpose of this investigation was to use electromyography (EMG)
combined with pattern classification procedures to examine differences in
activation among the superficial quadriceps femoris muscles during fatiguing
concentric isokinetic muscle actions. Ten men (mean ± SD
age=22.4 ± 1.2 yrs) and six women
(mean ± SD age=23.0 ±
2.1 yrs) performed 50 consecutive maximal concentric isokinetic
muscle actions of the dominant leg extensors at a velocity of
180°/s. During each muscle action, bipolar surface EMG
signals were detected from the vastus lateralis (VL), rectus femoris (RF), and
vastus medialis (VM). These signals were then processed with a wavelet
analysis, and the resulting intensity patterns were classified using pattern
classification procedures. The results demonstrated that the EMG intensity
patterns could be separated into muscle-specific groups with rates ranging from
89–100% and classified with accuracy levels between 84% and 100%.
These findings showed muscle-specific activation patterns in the quadriceps
femoris muscles, despite common femoral nerve innervation. These differences in
activation likely reflected the different roles of each muscle during leg
extension. Future studies need to be done to further examine these differences
during other activities that include movement at the hip joint, such as running
and cycling.
