Agten A, et al. - Via a cross-sectional study conducted in the REVAL Rehabilitation Research Center, Hasselt University, Diepenbeek, Belgium of 20 individuals with nonspecific chronic low back pain (NSCLBP) and 18 healthy controls, experts examined variations in muscle fiber type composition between individuals with NSCLBP and healthy controls for the lumbar erector spinae (ES) and multifidus (MF) muscle. No important variations between both groups about anthropometric data were seen. No notable between group variations for cross-sectional fiber areas (CSA) in the ES were noted. People with NSCLBP exhibited an unimportant rise in the number of type I muscle fibers, and a notable reduction in the number of type IIx muscle fibers in the ES muscle. Individuals with NSCLBP also exhibited a trend toward a higher relative CSA (RCSA) for type I fibers and a considerably lower RCSA for type IIx fibers. No notable between group variation within the MF was observed. Relative to the secondary outcome measures, an important between group variation in activity level and isokinetic back muscle strength was noted. In conclusion, this was the first study to investigate muscle fiber type features in both the ES and MF muscle of individuals with NSCLBP. The paraspinal muscles of individuals with NSCLBP appears to show a greater oxidative potential on the basis of a rise of the number type I fibers at the expense of type IIx glycolytic fibers on the basis of muscle fiber features.