Insights into Anaerobic Power Reserve On Relationships with Exercise Tolerance, Work Above Critical Power, and Accumulated Oxygen Deficit in Endurance-Trained Male Cyclists: A Pilot Study

The anaerobic power reserve (APR) model seeks to account for the heterogeneity in athletes' anaerobic characteristics. However, its relationship with exercise tolerance across various durations and with anaerobic markers remains unclear. Therefore, we investigate the relationship between APR, exercise tolerance, work above critical power (W'), and maximal accumulated oxygen deficit (MAOD) in male cyclists. We further analyzed these relationships replacing maximal aerobic power (MAP) with critical power (CP) as the lower boundary of the power reserve, defining a so-called maximal power reserve (MPR). After preliminary tests, 19 endurance-trained male cyclists performed five trials to exhaustion (Tlim) at 130%, 115%, 100%, 85%, and 80% of MAP and Wingate test. APR and MPR correlated with all Tlims (<i>r</i> > 0.511, <i>p</i> < 0.03), except at 80% MAP. After fixing CP or MAP, only correlations with supramaximal Tlims remained significant (<i>r</i> > 0.703, <i>p</i> < 0.002). When peak power output (PPO) was fixed, only MPR correlated with Tlims at 130% and 115% MAP (<i>r</i> > 0.508, <i>p</i> = 0.037). Both APR and MPR were associated with MAOD and W' (<i>r</i> = 0.480-0.542, <i>p</i> ≤ 0.045), but only MPR remained significantly related to MAOD after adjusting for lower boundary (<i>r</i> = 0.488, <i>p</i> = 0.040). Our findings showed that in endurance-trained male cyclists, both power reserves relate to exercise tolerance, however their influence decreases for longer efforts. MPR exhibited a stronger link to anaerobic capacity compared to APR. The association between exercise tolerance and APR/MPR appears largely driven by PPO, rather than the choice of lower boundary.