The research, published in BMC Sports Science, Medicine and Rehabilitation, also presents a nomogram intended to estimate the probability of the study’s defined knee outcome within the study population.
Participants were recruited between June 2023 and March 2024. Demographic and running-related information was collected through questionnaires, and each runner’s current knee status was defined based on KOOS scores. Of the 423 recreational runners included, 182, or 43.02 percent, met the study definition of current KOOS-defined knee status.
To examine which factors were associated with this outcome, the researchers performed univariable and multivariable logistic regression analyses. In the fully adjusted association model, five factors showed at least one statistically significant category contrast: weekly running frequency, pre-running warm-up, full-marathon participation, previous knee or ankle discomfort, and an annual running volume of 600 to 900 kilometres.
The five significant factors were then jointly refitted in a separate multivariable logistic regression model to construct a nomogram, a visual tool that combines several predictors into a single estimated probability. In this jointly refitted model, previous knee or ankle discomfort showed the strongest association with the outcome, whereas pre-running warm-up was no longer statistically significant.
The model’s discrimination was assessed using the area under the receiver operating characteristic curve, which for a binary outcome is equivalent to the concordance index. The apparent AUC was 0.761, with a 95 percent confidence interval of 0.716 to 0.807. After internal validation with 1,000 bootstrap resamples, the optimism-corrected C-index was 0.737, indicating moderate discrimination that is somewhat lower than the apparent value.
Calibration was also evaluated. Bootstrap calibration showed generally reasonable agreement between the probabilities estimated by the model and the probabilities actually observed in the data. In addition, decision-curve analysis in the development sample suggested potential net benefit across a broad range of examined threshold probabilities, although these performance evaluations were carried out in the same sample used to develop the model.
The authors conclude that several running-related and health-related characteristics were associated with current KOOS-defined knee status, and that the internally validated nomogram provides a preliminary visual method for estimating the probability of this status within the study population. They emphasise that prospective evaluation and external validation are required before the model can be used to predict future injury or support routine clinical decision-making.
Because the study is cross-sectional, it captures associations at a single point in time and cannot establish causal relationships between running habits and knee status.
For recreational runners and clinicians, the study offers a structured picture of which characteristics were linked to current KOOS-defined knee status in this population, with previous knee or ankle discomfort standing out as the factor most strongly associated with the outcome in the final model. The nomogram’s real-world usefulness, however, will depend on the prospective and external validation the authors call for before any clinical application.
Subject of Research: Factors associated with KOOS-defined knee status among recreational runners
Article Title: Factors associated with current KOOS-defined knee status among recreational runners: a cross-sectional study
Article References: Zhu, L., Mo, F., Zhang, C., Li, X., & Lan, C. (2026). Factors associated with current KOOS-defined knee status among recreational runners: a cross-sectional study. BMC Sports Science, Medicine and Rehabilitation. https://doi.org/10.1186/s13102-026-02192-9
Image Credits: AI Generated
DOI: 10.1186/s13102-026-02192-9
Keywords: recreational running, knee health, KOOS, cross-sectional study, nomogram, logistic regression, running volume, injury risk factors, bootstrap validation, sports medicine, Factors, associated
News Source: Ophelia Keating. (October 29, 2026). Running habits linked to knee status in recreational runners, cross-sectional study finds. Scienmag.
