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Updated: Jul 15, 2026
Conducting Maximal and Submaximal Endurance Exercise Testing to Measure Physiological and Biological Responses to Acute Exercise in Humans
Published on: October 17, 2018
Acute caffeine supplementation and cycling time-trial performance across different task durations: a systematic
Zhenyu Wang1, Jingwen Zhang1, Changmo Cho2
1Department of Physical Education, Graduate School, Keimyung University, Daegu, Republic of Korea.
Background/Objectives:
Acute caffeine (CAF) ingestion may enhance cycling time-trial (TT) performance, but its ergogenic effects may be expressed differently across TT tasks with markedly different durations. Utilizing the power-duration relationship and critical power framework, this systematic review and meta-analysis examined the effects of acute pre-exercise CAF ingestion on cycling TT performance and compared effect estimates between prespecified short-duration (≤10 min) and long-duration (≥20 min) TT tasks.
Methods:
Following PRISMA 2020 guidelines and PROSPERO registration (CRD420261334904), five databases were searched from inception to 14 January 2026 for randomized, double-blind, placebo-controlled trials in healthy cyclists. Random-effects meta-analyses were conducted using standardized mean differences (SMDs; Hedges' g) for TT completion time and mean power output.
Results:
Twenty-three trials were included. CAF reduced TT completion time (SMD = -0.32, 95% CI -0.49 to -0.16; I 2 = 0%) and increased mean power output (SMD = 0.20, 95% CI 0.02 to 0.38; I 2 = 0%). Completion time improved in both short-duration (SMD = -0.30) and long-duration (SMD = -0.37) TTs, with no significant subgroup difference. Mean power output increased significantly in short-duration TTs (SMD = 0.27) but did not reach statistical significance in long-duration TTs (SMD = 0.07), although the between-subgroup difference was not significant. Sensitivity analyses yielded consistent results.
Conclusions:
The findings of the present study indicate that acute pre-exercise caffeine ingestion can provide a small but practically meaningful benefit for cycling TT performance, primarily reflected in reduced completion time across the included prespecified short-duration (≤10 min) and long-duration (≥20 min) TT tasks. The increase in mean power output was mainly evident in short-duration TT tasks, suggesting that improved average mechanical power output may play an important role in short-duration performance gains, whereas improvements in long-duration TT tasks may involve additional performance-related factors beyond mean power output.
Systematic Review Registration:
https://www.crd.york.ac.uk/PROSPERO/view/CRD420261334904, identifier CRD420261334904.
