Caffeine increases motor output entropy and performance in 4 km cycling time trial

Abstract

Caffeine improves cycling time trial performance through enhanced motor output and muscle recruitment. However, it is unknown if caffeine further increases power output entropy. To investigate the effects of caffeine effects on cycling time trial performance and motor output entropy (MOEn), nine cyclists (VO 2MAX of 55 ± 6.1 mL. kg .-1 min-1) performed a 4 km cycling time trial (TT 4km) after caffeine and placebo ingestion in a counterbalanced order. Power output data were sampled at a 2 Hz frequency, thereafter entropy was estimated on a sliding-window fashion to generate a power output time series. A number of mixed models compared performance and motor output entropy between caffeine and placebo every 25% of the total TT 4km distance. Caffeine ingestion improved power output by 8% (p = 0.003) and increased MOEn by 7% (p = 0.018). Cyclists adopted a U-shaped pacing strategy after caffeine ingestion. MOEn mirrored power output responses as an inverted U-shape MOEn during the time trial. Accordingly, a strong inverse correlation was observed between MOEn and power output responses over the last 25% of the TT 4km (p < 0.001), regardless of the ingestion, likely reflecting the end spurt during this period (p = 0.016). Caffeine ingestion improved TT 4km performance and motor output responses likely due to a greater power output entropy.

Active ischemic pre‐conditioning does not additively improve short‐term high‐intensity cycling performance when combined with caffeine ingestion in trained young men

“…For example, complete blockade of group III/IV afferent feedback during cycling exercise elicits a similar pattern of high power output during the initial part followed by a drop in power output below the control condition during the latter part of a 5‐km time trial (∼8 min duration) (Blain et al., 2016). Other studies utilizing cycling time trials have observed similar effects on pacing with caffeine (Correia‐Oliveira & Lopes‐Silva, 2022; Ferreira Viana et al., 2020; Jessen et al., 2021). Plasma lactate, K + and pH were unaltered between trials suggesting that muscle lactate or K + transport capacity were not responsible for the altered pacing strategy.…”