Muscle Fatigue Assessment in Chronic Low Back Pain

Muscle fatigue assessment in chronic low back pain (CLBP) encompasses objective evaluation of paraspinal endurance, metabolic responses and neuromuscular control to better understand pathophysiology and guide treatment. Key clinical tests such as the Biering-Sorensen trunk extension and flexion-extension assessments reveal increased fatigability and altered activation patterns in the erector spinae complex. Advances in surface electromyography (sEMG) and near-infrared spectroscopy have enabled quantification of median frequency shifts, amplitude changes and local tissue oxygenation during sustained or cyclic back-extension tasks. These metrics serve as digital biomarkers to detect early muscle deterioration, monitor disease progression and tailor rehabilitation strategies. Emerging wearable and mobile technologies promise greater accessibility and real-time feedback, addressing challenges of cost, portability and standardisation. Understanding these assessments is essential for clinicians and researchers aiming to reduce disability, enhance functional recovery and mitigate the global burden of CLBP.

Research from Nature Portfolio

Recent studies have compared paraspinal muscle oxygenation and mechanical efficiency in individuals with CLBP and healthy controls, demonstrating lower tissue oxygenation and reduced efficiency during standardized trunk-extension exercise. The decline in haemoglobin-myoglobin concentration and mechanical efficiency was linked to increased pain sensation, suggesting that impaired local metabolism contributes to fatigability and functional limitation. These findings highlight muscle oxygenation metrics as promising objective indicators of endurance deficits and pain exacerbation in CLBP, offering targets for personalised rehabilitation and monitoring.

Muscle Fatigue Assessment in Chronic Low Back Pain publication trend

The graph below shows the total number of articles in muscle fatigue assessment in chronic low back pain across all publications each year (not limited to Nature Index journals).

Technical terms

Surface electromyography (sEMG): A non-invasive technique for recording electrical activity produced by skeletal muscles via electrodes placed on the skin.

Median frequency (MF): A spectral measure of the frequency content of an sEMG signal that decreases as muscle fibres fatigue.

Near-infrared spectroscopy (NIRS): An optical method for assessing tissue oxygenation and haemoglobin dynamics in muscles.

Mechanical efficiency: The ratio of work output to metabolic energy expenditure during exercise.

Biering-Sorensen test: A clinical endurance assessment in which a person maintains a horizontal trunk extension while prone, used to evaluate back extensor muscle fatigue.

References

1. Potential of a New, Flexible Electrode sEMG System in Detecting Electromyographic Activation in Low Back Muscles during Clinical Tests: A Pilot Study on Wearables for Pain Management. Sensors (2024).
2. The Back Muscle Surface Electromyography-Based Fatigue Index: A Digital Biomarker of Human Neuromuscular Aging?. Bioengineering (2023).
3. Paraspinal muscle oxygenation and mechanical efficiency are reduced in individuals with chronic low back pain. Scientific Reports (2024).