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Updated: Sep 21, 2025

Biomechanical Changes Related to Low Back Pain: An Innovative Tool for Movement Pattern Assessment and Treatment Evaluation in Rehabilitation
Published on: December 13, 2024
Muscle strength in Brazilian firefighters with non-specific chronic low back pain: A cross-sectional study
Flavia Marques Pedrosa1, Alexandre Lima de Araújo Ribeiro2, Daltro Izaias Pelozato de Oliveira1
1Universidade de Brasília (UnB), Campus UnB Ceilândia, Brasília, Brazil.
Background:
Imbalance between flexor and extensor muscles of the trunk could negatively influence spinal stability.
Objectives:
Investigate the strength balance between flexor and extensor muscles of the trunk in military firefighters with non-specific chronic low back pain (NSCLBP).
Methods:
One hundred and two male firefighters were assessed in an isokinetic dynamometer at 120°/s and 60°/s to investigate the balance ratio between flexor and extensor (F/E) muscles.
Results:
An F/E ratio of 0.72 (SD: 0.22; 95% CI: 0.67-0.76; SEM: 0.02) was observed at 60°/s and 0.94 (SD: 0.41; 95% CI: 0.85-1.03; SEM: 0.04) at 120°/s. The mean peak torque of the extensor muscles was 343.1 N.m/Kg (SD: 94.87; 95% CI: 322.8-363.5; SEM: 10.23) at 60°/s and 270.5 N.m/Kg (SD: 113; 95% CI 246.3-294.8; SEM: 12.18) at 120°/s. The mean peak torque of the flexor muscles was 232.4 N.m/Kg (SD: 53.86; 95% CI 220.8-243.9; SEM: 5.81) at 60°/s and 223.8 N.m/Kg (SD: 66.34; 95% CI 209.6-238.1; SEM: 7.15) at 120°/s. All torques generated by the extensor muscles were higher than the flexor muscles (p < 0.05).
Conclusions:
Firefighters with NSCLBP presented a normal F/E balance ratio and higher strength of extensor muscles of the trunk.

