The lumbar multifidus is characterised by larger type I muscle fibres compared to the erector spinae

Abstract

The metabolic capacity of a muscle is one of the determinants of muscle function. Muscle fiber type characteristics give an indication about this metabolic capacity. Therefore it might be expected that the lumbar multifidus (MF) as a local stabilizer contains higher proportions of slow type I fibers, compared to the erector spinae (ES) as a global mobilizer. The aim of this study is to determine the muscle fiber characteristics of the ES and MF to provide insight into their structural and metabolic characteristics, and thereby the functional capacity of both muscles. Muscle fiber type characteristics in the ES and MF were investigated with an immunofluorescence staining of the myosin heavy chain isoforms. In both the ES and MF, type I muscle fibers are predominantly present. The cross-sectional area (CSA) of type I muscle fibers is significantly larger in the lumbar MF compared to the ES. However, the mean muscle fiber type percentage for type I was not significantly different, which resulted in an insignificant difference in relative cross-sectional area (RCSA) for type I. No significant differences were found for all other muscle fiber types. This may indicate that the MF displays muscle fiber type characteristics that tend to be more appropriate to maintain stability of the spine. However, because we could not demonstrate significant differences in RCSA between ES and MF, we cannot firmly state that there are functional differences between the ES an MF based only on structural characteristics.

Sharp Changes in Muscle Tone in Humans Under Simulated Microgravity

“…In general, it may be concluded that changes in the tone of the back muscles progressively increased in the direction of the sterno-lumbar spine. However, research results show that the m. erector spinae muscle is homogeneous in composition along its entire length and contains 60–70% of type I fibers ( Mannion et al, 1997 ; Agten et al, 2020 ). Therefore, a smaller decrease in muscle tone in our study can not be explained by a lower content of tonic muscles in the lumbar region.…”

Paraspinal muscle pathophysiology associated with low back pain and spine degenerative disorders

“…Muscle fiber type composition helps determine the metabolic capacity and contractile characteristics of a muscle and demonstrates considerable plasticity, in general manifesting as a slow to fast transformation with reduced muscle usage and a fast to slow transformation with increased muscle usage 60 . In healthy male and female subjects aged 25 to 60, the paraspinal muscles (both multifidus and erector spinae) have demonstrated fiber type percentages of ~60, 23, and 15% for type 1, type IIA, and type IIX fibers, respectively 61 . The predominance of type 1 fibers implies that these muscles are relatively slow contracting and fatigue resistant compared to most appendicular muscles in which faster type 2 fibers are more prevalent.…”

“…60 In healthy male and female subjects aged 25 to 60, the paraspinal muscles (both multifidus and erector spinae) have demonstrated fiber type percentages of ~60, 23, and 15% for type 1, type IIA, and type IIX fibers, respectively. 61 The predominance of type 1 fibers implies that these muscles are relatively slow contracting and fatigue resistant compared to most appendicular muscles in which faster type 2 fibers are more prevalent. Other myofilament (eg, titin, nebulin), cytoplasmic (eg, dystrophin), and intermediate filament (eg, desmin) proteins also contribute to muscle function and are implicated in some muscle diseases; however, these proteins have not been investigated in relation to LBPDs and a thorough discussion of all relevant muscle proteins is outside the scope of this review.…”

Magnetic Resonance Imaging Evaluation Of The Degeneration Of The Multifidus And Erector Spinae Muscles In Patients With Chronic Mechanical Low Back Pain, Patients With Herniated Disc, And Healthy Individuals

“…Previous studies have shown an association between paraspinal muscle atrophy and LBP [2,15,16,25,28,29,47,49] and fat in ltration [16,17,48,[50][51][52][53]. Some of these studies have reported that in chronic LBP there is atrophy only in the LMF and there is no change in the LES [15,49,54,55], some have shown atrophy in both the LMF and LES [16], some have reported a smaller CSA of the LMF, psoas, and quadratus lumborum [47], and others have found no difference in the CSA of either the LMF and LES [22,[56][57][58]. Moreover, several researchers have reported that compared to healthy individuals there are no signi cant differences in the dimensions of paraspinal muscles [32,52,53,[59][60][61][62] or fat content [15,28,48].…”

“…In the process of muscle degeneration, a decrease in muscle dimensions, an increase in adipose tissue activation, and early fat in ltration are seen in the acute period, and in the subacute period, type I slow muscle bres transform to type II rapid muscle bres (type I bres are responsible for muscle strength and endurance), changes occur at the cellular and molecular level, brosis develops, and there is an increase in fat in ltration. The chronic period refers to the continued increase in atrophy of the muscle and muscle bres, brosis and fat in ltration [12,13,[20][21][22][23][24]. In a study by Pakkola et al, there was shown to be 9% fat in ltration in the paraspinal muscles of healthy middle-aged volunteers [16].…”