Affiliations: Clinic for Trauma, Hand and Reconstructive Surgery, Division of Motor Research, Pathophysiology and Biomechanics, Jena University Hospital, Jena, Germany
Correspondence:
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Corresponding author: Eduard Kurz, Clinic for Trauma, Hand and Reconstructive Surgery, Division of Motor Research, Pathophysiology and Biomechanics, Jena University Hospital, Bachstr. 18, 07743 Jena, Germany. Tel.: +49 3641 934 094; Fax: +49 3641 934 091; E-mail:Eduard.Kurz@med.uni-jena.de
Abstract: BACKGROUND: The Sorensen test is commonly used to assess back
muscle endurance capacity. However, the clinical value of this test,
requiring compensation of the entire upper body mass, is limited if pain
occurs. Therefore, a test variant using only portions of upper body mass
could be an alternative. OBJECTIVE: This study aimed to determine fatigue characteristics in
lumbar muscles during a modified Sorensen test utilizing only 50% of the
upper body mass and asked if localization-related effects of surface
electrodes in the assessment of lumbar muscle fatigue should be considered. METHODS: Thirty-two young (20-29 years) symptom-free men were
enrolled and asked to maintain only 50% upper body mass for 10 minutes.
Fatigue characteristics were bilaterally derived from four different lumbar
levels using Surface EMG. Side-specific and SEMG parameter-independent
repeated measures (four lumbar levels, nine time points) analyses of
variance were conducted. RESULTS: All participants were able to complete the test. Over
time, a spatial effect of fatigue-related amplitude alterations at the
respective segments could be observed. CONCLUSIONS: By using this modified Sorensen test, muscular fatigue
can be evoked. Electrophysiological assessment of lumbar fatigue should
consider spatial differences.
Keywords: SEMG, lumbar fatigue, spatial, back muscles
