Influences of muscle fiber composition and strength on EMG, spinal motion, and load acceleration during a repetitive lifting task.
Physical Therapy Education, University of Iowa, Iowa City, Iowa 1988 May; :1-80
The changes which occur over time in the erector spinae muscles of the lower back in the instantaneous fatigue state were studied in relation to the selected kinematic and kinetic features of lifting. The influences of muscle fiber composition and lifting strength on changes in electromyographic activity (EMG), spinal motion, and load acceleration during this time period were investigated. A total of 24 male volunteers participated in the study. A great deal of variability was noted in regard to EMG amplitude and EMG center frequency from the L3 erector spinae musculature in regard to the range of motion of the lumbar segment, and in regard to the maximum vertical acceleration applied to the load being lifted. A significant relationship was noted between the EMG amplitude and EMG center frequency trends during repetitive lifting but not among these EMG measures and trunk range of motion, maximum load acceleration, height, or weight. A significant relationship was noted between lifting strength of the subject and the amount of trunk range of motion at the beginning of the lifting session and to the height and weight of the subject. Finally, significant relations were noted between muscle fiber composition and the maximum vertical acceleration applied to the load at the beginning of the lifting session.
NIOSH-Grant; Musculoskeletal-system-disorders; Back-injuries; Humans; Repetitive-work
Physical Therapy Education University of Iowa S126 Westlawn Iowa City, Iowa 52242
Final Grant Report
NTIS Accession No.
Physical Therapy Education, University of Iowa, Iowa City, Iowa
University of Iowa, Iowa City, Iowa