Endurance Training of Trunk Extensor Muscles

• Published in: Physical therapy Vol. 73; no. 1; pp. 3 - 00017
• Main Authors: MOFFROID, M.T, HAUGH, L.D, HAIG, A.J, HENRY, S.M, POPE, M.H
• Format: Journal Article
• Language: English
• Published: Alexandria, VA American Physical Therapy Association 01.01.1993; Oxford University Press
• Subjects: Adult; Anthropometry; Back; Biological and medical sciences; Electromyography; Exercise; Fatigue - physiopathology; Female; Humans; Isometric Contraction; Medical research; Medical sciences; Minicomputers; Muscle strength; Muscular system; Physical Endurance; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Signal Processing, Computer-Assisted; Training; Physical exercise; Measurement; Physical training; Lumbar spine; Test; Spine; Isometric muscular contraction; Female; Electromyography; Striated muscle
• ISSN: 0031-9023; 1538-6724
• DOI: 10.1093/ptj/73.1.3

The purpose of this study was to assess the effects of an endurance exercise protocol on the isometric holding time of the trunk extensor muscles (mechanical fatigue measure) and on the recorded median frequency (MF) measurements from the surface electromyogram (physiological fatigue measure). Twenty-eight healthy female volunteers were selected to participate in the study. The subjects were stratified by activity level and then assigned to an exercise or a control group and tested at weeks 0, 3, and 6. Reliability (r) of the measurements, established by testing each subject twice at week 0, was .87. Exercise group subjects trained at home twice daily for 6 weeks, progressing by established protocol. The exercise group subjects increased their isometric holding time by 22% after 6 weeks. The control group showed no significant changes. The home program was believed to be effective for increasing isometric endurance of the trunk extensors, measured by holding time. The MF measurements prior to and just after a fatiguing contraction remained stable over time. The change in the slope of the MF with fatigue did not reach statistical significance. This physiologic measure of fatigue did not show commensurate changes with training in this group of subjects. Possible reasons for the results are discussed.