The effects of ageing on fatigue and endurance of the spinal extensor muscles: a systematic review and meta-analysis.

The endurance capacity of the spinal extensor muscles plays a key role in maintaining spinal function. This systematic review and meta-analysis aims to synthesise current evidence on how ageing influences fatigue of the spinal extensor muscles, addressing the inconsistent findings reported across existing studies. Medline, EMBASE, PubMed, Web of Science and CINAHL Plus databases were searched from their inception to 28 June 2025. Cross-sectional studies assessing fatigue of the spinal extensor muscles of healthy older adults (>60 years) versus younger adults were included. Methodological quality was evaluated using the Appraisal Tool for Cross-Sectional Studies and the GRADE approach was applied to assess the certainty of evidence. Results were synthesised using both narrative and quantitative approaches. A random-effects meta-analysis was conducted for endurance time. The PRISMA guidelines were followed for reporting. Of the 1253 records screened, 13 studies were included, with 9 contributing to the meta-analysis. The meta-analysis, supported by moderate certainty of evidence, revealed a significant reduction in endurance time of the back extensor muscles during sustained isometric contractions in older adults compared to younger controls (MD = -41.31; 95% CI: -64.04; -18.57). The remaining outcomes were synthesised narratively: electromyograph (EMG) related measures showed mixed findings, likely due to methodological variability across studies, while force decline and Borg ratings were reported in only a few studies. This systematic review revealed that the endurance time of the back extensor muscles is reduced during isometric tasks in older adults. However, inconsistent EMG findings limit our understanding of the neuromuscular mechanisms underlying this decline.