Author(s): SONDERMANN, Y., THRON, M., QUITTMANN, O.J., BECKER, T., BÖER, L., SCHREIBER, S., WORTH, L., WOLL, A., ALTMANN, S., Institution: KARLSRUHE INSTITUTE OF TECHNOLOGY, Country: GERMANY, Abstract-ID: 2756

INTRODUCTION:
Contemporary models of endurance performance propose that key physiological determinants deteriorate during prolonged exercise (1). The capacity to resist such deterioration, i.e. durability, has emerged as a critical performance factor in professional cycling [2]. However, research on durability has predominantly focused on aerobic determinants [3], while markers of anaerobic metabolism remain largely unexplored. Therefore, this study aimed to determine (i) the extent to which anaerobic power and anaerobic capacity deteriorate following prolonged cycling, and (ii) whether changes in short-duration time-trial performance can be explained by anaerobic measures assessed in fresh and fatigued states.
METHODS:
Thirty-six trained cyclists (16 female) completed two laboratory visits. During visit one, participants performed a submaximal incremental test to determine lactate thresholds (LT1, LT2), followed by a Wingate test to assess peak and mean power output (PPO, PWIN) and peak blood lactate concentration (LaWIN). Participants were subsequently familiarised with countermovement jump (CMJ) testing and a 4-min time-trial (TT). TT-derived outcomes included accumulated oxygen deficit (AOD), oxygen cost (OC), V̇O₂peak, mean power output, and peak blood lactate concentration (LaTT). During visit two, CMJ and TT performance were assessed before and after 2 h of prolonged cycling performed at 33% of the difference between LT1 and LT2. During prolonged cycling, respiratory gases and lactate concentrations were measured periodically every 15 minutes. Participants consumed water ad libitum and ingested 15 grams of carbohydrates every 15 minutes. Differences between conditions were assessed using paired t-tests with Cohen’s d reported as effect size. Associations between fatigue-induced changes and TT performance decline were examined using linear regression.
RESULTS:
Mean TT power output decreased from 321±71 to 290±65 W following prolonged cycling (−9.6%, p<0.001, d=1.54). LaTT (−25.9%, d=1.60), AOD (−24.5%, d=1.09), and CMJ (−4.0%, d=0.90) were significantly reduced (all p<0.001). V̇O₂peak decreased (−3.3%, p<0.001, d=0.96), while oxygen cost increased (+5.7%, p<0.001, d=0.81). Regression analyses revealed that reductions in LaTT and AOD explained 64.6% (p<0.001) and 38.2% (p<0.001) of the variance in TT power decline, respectively. The increase in OC accounted for 46.6% of the variance (p<0.001), while the reduction in V̇O₂peak explained 16.6% (p=0.017). In contrast, when assessed unfatigued, markers of anaerobic metabolism were not significantly associated with the magnitude of TT performance decline (all p≥0.13)
CONCLUSION:
Deterioration of short endurance cycling performance following prolonged cycling is strongly associated with alterations in both anaerobic and aerobic markers. However, anaerobic markers assessed in the unfatigued state did not predict durability.

[1] Jones (2023) J Physiol
[2] Van Erp et al. (2021) Med Sci Sports Exerc
[3] Zanini et al. (2025) Scand J Med Sci Sport