Author(s): PAPANDREOU, A.1,2, PARADISIS, G.1, PHILIPPOU, A.2, ZACHAROGIANNIS, E.1, Institution: NATIONAL AND KAPODISTRIAN UNIVERSITY OF ATHENS, Country: GREECE, Abstract-ID: 503

INTRODUCTION:
Performance in the 500-m kayak event relies on the integration of aerobic and anaerobic metabolism, functional power production, paddling economy, and the ability to sustain high intensities close to the second ventilatory threshold (VT₂). High-intensity interval training (HIIT) and sprint interval training (SIT) are widely used time-efficient strategies; however, the interaction between functional performance indices and molecular adaptations to different intensity domains remains insufficient regarding elite paddlers.
METHODS:
Thirty-two national-level kayak athletes were allocated to four groups: HIIT (110% VO₂peak), SIT (≈140% VO₂peak/VO₂max), COMB (HIIT+SIT +continuous training), and control (CON). Athletes completed 18 training sessions over six weeks. Measurements included VO₂max, blood lactate concentration ([La²⁺]), HRmax, power output at VO₂max (POVO₂max), paddling economy (POPE), power output at VT₂ (POVT₂), and 500-m time-trial performance, assessed at PRE, POST, and after 15 and 30 days of detraining. Resting concentrations of IL-6 and VEGF-A were measured at PRE and POST. Data were analyzed using two-way repeated-measures ANOVA and Pearson correlation analysis (ΔPOST–PRE).
RESULTS:
VO₂max exhibited only modest, non-significant time effects, primarily in the HIIT group. In contrast, functional determinants of performance (POVO₂max, POPE, and POVT₂) improved significantly in HIIT, SIT, and COMB, accompanied by meaningful improvements in 500-m performance, with partial attenuation during detraining. Resting IL-6 decreased significantly following HIIT and SIT, while VEGF-A increased significantly only after HIIT. Correlation analysis identified VT₂ as a central determinant of performance, with changes in POVT₂ strongly associated with changes in 500-m time.
CONCLUSION:
HIIT, SIT, and combined training induce substantial improvements in functional performance determinants and 500-m kayaking performance, despite minimal changes in VO₂max. VT₂ emerges as a functional “hub” integrating central and peripheral adaptations, including power production, economy, and molecular responses (IL-6, VEGF-A), appears to be a more sensitive indicator of competitive performance than VO₂max in national-level kayak athletes.