We found conflicting data regarding the validity of methods used to examine back muscle fatigue .
The Biering-Sorensen test  , performed in conjunction with surface electromyography spectral analysis , turned out to be the most widely used and comparatively , the most optimal modality currently available to assess objective back muscle fatigue in daily clinical practise , even though critical limitations are discussed .
Implication s for Rehabilitation Despite its limitations , the Biering-Sorensen test is currently the most used , convenient and easily available fatiguing test for lumbar muscles .
Pooled mean frequency and half-width of the spectrum are currently the most valid electromyographic parameters to assess fatigue in chronic non-specific low back pain .
PURPOSE This systematic literature review aim ed at examining the validity and applicability in everyday clinical rehabilitation practise of methods for the assessment of back muscle fatiguability in patients with chronic non-specific low back pain ( CNSLBP ) .
Chronic Low Back Pain-Associated Paraspinal Muscle Dysfunction is not the Result of a Constitutionally Determined “Adverse” Fiber-type Composition
Study Design . Investigative case control study . Objectives . To determine whether excessive paraspinal muscle fatigue in chronic low back pain results from a paucity of muscle type I fiber content . Summary of Background Data . Paraspinal muscle function is vital for spinal protection . Prospect i ve studies suggest that excessive paraspinal muscle fatigability may increase risk of first-time low back pain . As contractile performance of the paraspinal muscles is governed by their constitutionally determined fiber composition , the question arises whether a constitutionally determined “ adverse ” composition could predispose to low back pain through impaired spinal protection . Methods . Thirty-five male patients with chronic low back pain were compared with 32 male control patients of similar age and anthropometry . During Sorensen and 60 % of maximum voluntary isometric contraction fatigue tests , median frequency declines in the  paraspinal muscle surface electromyograph signal were monitored and correlated with muscle histomorphometry . Results . Patients were weaker than controls during maximum voluntary isometric contractions ( 84.47 [28.44]vs . 98.74 [ 18.11 ] kg , respectively ; P = 0.02 ) and more fatigable during their Sorensen tests ( endurance time 105.29 [28.53]vs . 137.50 [ 40.38 ] sec , respectively ; P < 0.01 ) . There were no between-group differences in median frequency declines during the Sorensen ( −0.37 [0.16]vs . −0.36 [0.12]%.sec−1 ) or 60 % maximum voluntary isometric contraction ( −0.42 [0.31]vs . −0.51 [0.29]%.sec−1 ) tests , for patients and controls , respectively . There were no between-group differences in the percent number of paraspinal muscle type I fibers ( 64 [11]vs . 64 [9]% ) or the percent area occupied by type I fibers ( 67 [11]vs . 69 [9]% ) , for patients and controls , respectively . Type I and II muscle fiber narrow diameters were similar for both groups . Conclusion . In the patients with chronic low back pain tested , their associated paraspinal muscle dysfunctionwas not the result of a constitutionally determined “ adverse ” fiber type composition
We found conflicting data regarding the validity of methods used to examine back muscle fatigue .
The Biering-Sorensen test  , performed in conjunction with surface electromyography spectral analysis , turned out to be the most widely used and comparatively , the most optimal modality currently available to assess objective back muscle fatigue in daily clinical practise , even though critical limitations are discussed .
Implication s for Rehabilitation Despite its limitations , the Biering-Sorensen test is currently the most used , convenient and easily available fatiguing test for lumbar muscles .
Pooled mean frequency and half-width of the spectrum are currently the most valid electromyographic parameters to assess fatigue in chronic non-specific low back pain .
PURPOSE This systematic literature review aim ed at examining the validity and applicability in everyday clinical rehabilitation practise of methods for the assessment of back muscle fatiguability in patients with chronic non-specific low back pain ( CNSLBP ) .