Flexion-Relaxation Phenomenon in Children and Adolescents With and Without Nonspecific Chronic Low Back Pain: An Electromyographic and Kinematic Cross-Sectional Comparative Study

A cross-sectional comparative study. OBJECTIVE: This study aimed to investigate the flexion-relaxation phenomenon (FRP), in standing trunk flexion and slumped sitting tasks, by comparing children and adolescents suffering from nonspecific chronic low back pain (NSCLBP) with controls (CTRL).