We are writing to provide a re-analysis of the data concerning adductor strength monitoring during congested periods in rink hockey players, published by Quintana-Cepedal et al., 2024 in Apunts Sports Medicine.1 For the main aim, to monitor adductor strength throughout a tournament, our previous report utilized independent simple linear regressions for male and female cohorts to test the effect of cumulative time on adduction strength (N) during the 5-second squeeze test. Modern sports science statistics increasingly favour integrated approaches that account for the nested nature of longitudinal data.2,3 Simple linear regression, while informative, often fails to account for inter-individual variability and the correlation between repeated measures within the same participant. Transitioning to a linear mixed-effects model allows us to separate the noise of individual baseline strength from the signal of the actual fatigue trend. This provides a more rigorous estimation of the true physiological decline due to accumulated fatigue.

Data re-analysis was conducted in the R Statistical Software with the following packages: lmerTest, lme4, emmeans, see, performance, and ggplot2. We utilized the Sex × Time interaction as a fixed effect, accounting for dependency by modelling participant ID as random intercepts. Model’s R2marginal, R2conditional, and root mean squared error (RMSE) were extracted to quantify the proportion of variance explained by the experimental factors versus the entire model structure, while simultaneously evaluating the absolute fit and predictive accuracy of our longitudinal estimates. This re-analysis confirms a significant time × sex interaction (β = −0.51, p = 0.001) (Fig. 1), the model demonstrated a robust fit (R2marginal = 0.412, R2conditional = 0.737, RMSE = 28.29). Simple slopes analysis revealed that males experienced a significant decline in adduction strength (β = −0.67; 95% CI = −0.86 to −0.48), while females maintained stable strength levels throughout the monitored period (β = −0.16, 95% CI = −0.39 to 0.07). A direct comparison of the slopes confirmed that the rate of decline was significantly steeper in the male group (Contrast = 0.51, p = 0.0012).

Fig. 1.

Interaction of time and sex on adductor squeeze strength. Estimated marginal means (solid lines) and 95% confidence intervals (shaded area) showing the decline in squeeze strength over a match-congested period for males (blue) and females (red). Thin lines represent the individual trajectories of participants across the study period.

Crucially, while the statistical power and precision of the estimates have improved, the fundamental conclusion remains unchanged: Handheld dynamometry seems to be a valid tool capable of detecting adductor strength deficits caused by cumulative load. This re-analysis not only reinforces our original claims but provides a mathematically superior foundation for adduction strength monitoring in rink hockey athletes. Moving forward, we recommend that future studies employing similar methodologies adopt this analytical approach to ensure more robust and comparable data across athletic populations.