Statistical analysis

Data was analyzed using the R (version 3.5.3) programming language. Normal distribution was verified using the Shapiro–Wilk test for small samples across all parameters. A 3x3 two-way repeated-measures ANOVA using the Afex package was performed to determine the effect of different treatments (CON, LOW, HIGH) over time (PRE, POST, POST30) on all measured variables. The assumption of sphericity was assessed using the Mauchly test. Whenever the assumption of sphericity was violated, the degrees of freedom were corrected using the Greenhouse-Geisser correction (GGe). Post-hoc tests were performed as pairwise comparisons using Tukey’s adjustment within the Emmeans package to determine the differences between single treatments at different time points. Standardized changes in the mean of each measure were used to assess magnitudes of effects and were calculated using Cohen’s d and then interpreted using thresholds of 0.2, 0.5, 0.8 for small, moderate and large, respectively \cite{Batterham2006}. An effect size of ±0.2 was considered the smallest worthwhile effect with an effect size of <0.2 considered to be trivial. The effect was considered unclear if its 95% confidence interval overlapped the thresholds for small positive and small negative effects \cite{Batterham2006}. Statistical significance was set at p < 0.05 for all analyses.