Sex-Related Differences in Human Tendon Stiffness: A Systematic Review and Meta-analysis.

Background: The identification of sex-specific differences in tendon stiffness may facilitate better understanding of the underlying mechanisms of differences in tendon injuries between sexes. Consequently, the objective of this meta-analysis was to examine the influence of sex on human tendon stiffness.

Methods: Literature search was conducted for the systematic review and meta-analysis through the PubMed, Web of Science and Scopus electronic databases. Studies comparing tendon stiffness in males and females written in English were included. The methodological quality assessment of the included studies was conducted with the adapted version of the Newcastle-Ottawa Scale for cross-sectional studies. The standardised mean difference (SMD) with corresponding 95% confidence intervals (CIs) was employed to quantify the effects between males and females.

Results: A total of 32 studies that met the inclusion criteria were analysed in the study. Four studies were classified as of high quality, 27 as of medium quality, and the remainder as of low quality. The Achilles tendon stiffness (SMD = - 0.88, 95% CI = - 1.30, - 0.46; p < 0.001) and patellar tendon stiffness (SMD = - 0.62, 95% CI = - 1.17, - 0.07; p = 0.03) were found to be higher in males compared to females. Conversely, the values for quadriceps tendon stiffness were similar across sexes (SMD = - 0.19, 95% CI = - 1.14, 0.74; p = 0.69).

Conclusion: The findings of this meta-analysis indicate that males exhibit greater Achilles and patellar tendon stiffness than females. The observed differences regarding Achilles and patellar tendon stiffness may have an effect on the differing prevalence of tendon injury between males and females.

Supplementary information: The online version contains supplementary material available at 10.1007/s43465-025-01398-2.