Category: Biomedical Sciences
Objectives: The impact of aging is not well understood, yet may hold clues to both normal aging and chronic low back pain (cLBP). In sustained high submaximum back extensions, spectral surface electromyographic (SEMG) fatigue, a surrogate measure of glycolytic muscle metabolism, may be decreased with increasing age, but increased with cLBP. Previous research by our group found the spectral SEMG fatigue method able to descriminate between older and younger back extensor muscles function, despite the fact that younger and older individuals demonstrated comparable maximum back extension strength scores. Thus, this study sought to investigate whether the spectral SEMG back muscle fatigue method would be as sensitive as it is in healthy individuals to detect age- and sex-specific differences in neuromuscular and muscle metabolic functions in patients with cLBP in a reliable way.
Design: With participants seated on a dynamometer (20º trunk anteflexion), paraspinal SEMG activity was recorded bilaterally from the multifidus (L5), longissimus (L2) and iliolumbalis (L1) muscles during isometric, sustained back extensions loaded at 80% of maximum from a total of 117 younger (58 females) and 112 older (56 females) cLBP individuals. Tests were repeated after 1-2 days and 6 weeks. Median frequency (MF), the spectral SEMG variable indicating neuromuscular fatigue, was analyzed.
Results: Maximum back extensor strength scores were comparable between younger and older individuals. Significantly less MF-SEMG back muscle fatigue was observed in older than younger, or in older female than male cLBP individuals. Relative reliability was excellent, but absolute reliability appeared large for this SEMG-fatigue measure.
Conclusions: Findings suggest that cLBP unlikely masks the age-specific diagnostic potential of the MF-SEMG back extensor fatigue method. Thus, this method possesses a great potential for being further developed toward a valuable biomarker intended to very early detect back muscle function at risk for sarcopenia.
Gerold Ebenbichler– Research Associate Professor, Vienna Medical University, Department of Physical Medicine, Rehabilitation & Occupational Medicine
Richard Habenicht– Researcher, Karl-Landsteiner-Institute of Outpatient Rehabilitation Research,
Sara Ziegelbecker– Researcher, Karl-Landsteiner-Institute of Outpatient Rehabilitation Research,
Josef Kollmitzer– Professor, Technical School of Engineering
Patrick Mair– Researcher, Department of Psychology, Harvard University
Thomas Kienbacher– Head of reserach, Universitätsdozent, Karl-Landsteiner-Institute of Outpatient Rehabilitation Research