Endpoint
Time-trial completion time
CAT:outcome/time-trial-performancereported in s7 findings from 3 compounds
What moved it
How to read these marks7 findings · 3 compounds · 3 null · by evidence strength
| Compound | Direction | Findings | Strongest evidence |
|---|---|---|---|
| caffeine | down 4 · no effect 1 | 5 | Evidence strength: moderate. Human evidence with one recorded weakness, or capped at moderate by its design or by unread numbers. |
| astaxanthin | no effect | 1 | Evidence strength: moderate. Human evidence with one recorded weakness, or capped at moderate by its design or by unread numbers. |
| magnesium(2+) | no effect | 1 | Evidence strength: very limited. Human evidence with major recorded weaknesses, or non-human, uncontrolled or unverified evidence. |
Reported to move it
4 findings
caffeine — decreases
ModerateEvidence strength: moderate. Human evidence with one recorded weakness, or capped at moderate by its design or by unread numbers.Findingreplicated ×3“Both low and moderate caffeine doses significantly reduced time-trial completion time relative to placebo.”
Quoted verbatim from Dose-Response Effect of Oral Caffeine Use on Aerobic Exercise Performance: A Systematic Review and Meta-Analysis.. - Study
- meta-analysis
- Dose
- Acute pre-exercise oral anhydrous caffeine; low (3 mg/kg or less) and moderate (4-6 mg/kg) dose strata
- Population
- Healthy adults aged 18-59 years performing aerobic time-trial tests
Dose-Response Effect of Oral Caffeine Use on Aerobic Exercise Performance: A Systematic Review and Meta-Analysis.2026PMID:42356375Permalink
caffeine — decreases
Very limitedEvidence strength: very limited. Human evidence with major recorded weaknesses, or non-human, uncontrolled or unverified evidence.Findingreplicated ×3“Both doses of caffeine had a similar ergogenic effect relative to placebo: performance time decreased by a mean of 1.2% (95% likely range 0.4-1.9%); the corresponding increase in mean power was 2.7% (0.4-5.0%).”
Quoted verbatim from Enhancement of 2000-m rowing performance after caffeine ingestion.. - Study
- crossover
- Participants
- 8
- Dose
- 6 or 9 mg/kg body mass caffeine, 1 h before exercise
- Population
- competitive oarsmen
Enhancement of 2000-m rowing performance after caffeine ingestion.2000PMID:11079528Permalink
caffeine — decreases
Very limitedEvidence strength: very limited. Human evidence with major recorded weaknesses, or non-human, uncontrolled or unverified evidence.Findingreplicated ×3“Overall, 4 mg·kg caffeine decreased cycling time by 3% (mean ± SEM) versus placebo (17.6 ± 0.1 vs 18.1 ± 0.1 min, P = 0.01).”
Quoted verbatim from Caffeine, CYP1A2 Genotype, and Endurance Performance in Athletes.. - Study
- crossover
- Participants
- 101
- Dose
- 4 mg/kg caffeine, single dose
- Population
- competitive male athletes, whole cohort pooled across CYP1A2 genotypes, 10-km cycling time trial
Caffeine, CYP1A2 Genotype, and Endurance Performance in Athletes.2018PMID:29509641Permalink
caffeine — decreases
Very limitedEvidence strength: very limited. Human evidence with major recorded weaknesses, or non-human, uncontrolled or unverified evidence.Findingreplicated ×3“CAF ingestion reduced the time to complete the 8-km C-PT from 34:26 ± 1:25 to 33:01 ± 1:24 min (P < 0.05).”
Quoted verbatim from Caffeine increases performance in cross-country double-poling time trial exercise.. - Study
- crossover
- Participants
- 10
- Dose
- 6 mg/kg caffeine
- Population
- 10 highly trained male cross-country skiers
Caffeine increases performance in cross-country double-poling time trial exercise.2013PMID:23591294Permalink
Measured, no effect detected
3 findings
astaxanthin — no detected effect on
ModerateEvidence strength: moderate. Human evidence with one recorded weakness, or capped at moderate by its design or by unread numbers.FindingNull result“The pooled estimate showed no significant effect of astaxanthin supplementation on time-trial performance (SMD = −0.17, 95% CI: −0.76 to 0.42), with moderate heterogeneity (I2 = 43.7%).”
Quoted verbatim from The Effects of Astaxanthin Supplementation on Exercise Recovery Biomarkers and Exercise Performance: A Systematic Review and Meta-Analysis.. - Study
- meta-analysis
- Population
- healthy adults and athletes; meta-analysis pooling 3 RCT comparisons
Effect -0.17 standardised mean difference, 95% CI -0.76 to 0.42
The Effects of Astaxanthin Supplementation on Exercise Recovery Biomarkers and Exercise Performance: A Systematic Review and Meta-Analysis.2026PMID:42197030Industry fundedPermalink
magnesium(2+) — no detected effect on
Very limitedEvidence strength: very limited. Human evidence with major recorded weaknesses, or non-human, uncontrolled or unverified evidence.FindingNull result“The time taken to complete the 10 km time trial was not different ( p = 0.89) between the placebo (1282 ± 126 s) and magnesium (1281 ± 97 s).”
Quoted verbatim from Short-Term Magnesium Supplementation Has Modest Detrimental Effects on Cycle Ergometer Exercise Performance and Skeletal Muscle Mitochondria and Negligible Effects on the Gut Microbiota: A Randomized Crossover Clinical Trial.. - Study
- crossover
- Participants
- 15
- Duration
- 9 days
- Dose
- magnesium chloride 300 mg (ReMag) twice per day for 9 days
- Population
- Healthy regularly exercising adults aged 18-40; primary outcome; self-paced simulated 10 km stationary cycle ergometer time trial
Short-Term Magnesium Supplementation Has Modest Detrimental Effects on Cycle Ergometer Exercise Performance and Skeletal Muscle Mitochondria and Negligible Effects on the Gut Microbiota: A Randomized Crossover Clinical Trial.2025PMID:40077784Industry fundedPermalink
caffeine — no detected effect on
InsufficientEvidence strength: insufficient. Mechanistic inference, no evidence found, or evidence weakened below very limited.FindingNull result“Time trial performance was not significantly different across the three caffeine doses or placebo (P = 0.249).”
Quoted verbatim from Dose response of caffeine on 2000-m rowing performance.. - Study
- crossover
- Participants
- 10
- Dose
- 2, 4, or 6 mg/kg caffeine or placebo, 60 min before a 2000-m rowing time trial
- Population
- competitive male rowers
Dose response of caffeine on 2000-m rowing performance.2010PMID:19952822Permalink
How it is measured
Time to complete a self-paced fixed-DISTANCE trial. Distance and modality recorded with each finding.
Measured, not recorded
- Subject
- time-trial completion time
- Measurements
- 6 measurements
- Recorded as a finding
- No
Show what was measured
Time-trial completion time
decreases
time-trial completion time (2.22 ± 2.59%; effect size = 0.41 ± 0.2)
PMID:29876876 · one of two readings recorded this
time-trial completion time
increases
Time-trial completion time showed improvements of 2.3 ± 2.6% with a small effect size of 0.28 ± 0.12
PMID:33388079 · one of two readings recorded this
time-trial completion time
decreases, p = 0.001
The meta-analysis of these studies demonstrated that the ingestion of low caffeine doses (ranging from approximately 1.3 to 3 mg·kg−1) resulted in a significant improvement in total time to complete aerobic time-trial tests (SMD = −0.27, 95% CI = −0.44 to −0.11, p = 0.001, I2 = 0%)
PMID:42356375 · one of two readings recorded this
time-trial completion time
decreases, p = 0.0001
The meta-analysis of these studies demonstrated that the ingestion of moderate caffeine doses (ranging from 4 to 6 mg·kg−1) produced a significant improvement in total time to complete aerobic time-trial tests (SMD = −0.52, 95% CI = −0.77 to −0.28, p < 0.0001, I2 = 73%)
PMID:42356375 · one of two readings recorded this
time-trial completion time
decreases, p = 0.00001
This exploratory analysis demonstrated statistically significant ergogenic effects in both trained individuals (SMD = −0.81; 95% CI = −1.59 to −0.02; p = 0.04; I2 = 91%) and highly trained individuals (SMD = −0.94; 95% CI = −1.35 to −0.53; p < 0.00001; I2 = 0%), with no statistically significant subgroup differences observed between categories (p = 0.77).
PMID:42356375 · one of two readings recorded this
time-trial completion time
decreases, p = 0.04
This exploratory analysis demonstrated statistically significant ergogenic effects in both trained individuals (SMD = −0.81; 95% CI = −1.59 to −0.02; p = 0.04; I2 = 91%) and highly trained individuals (SMD = −0.94; 95% CI = −1.35 to −0.53; p < 0.00001; I2 = 0%), with no statistically significant subgroup differences observed between categories (p = 0.77).
PMID:42356375 · one of two readings recorded this
Sources cited
7 papers
- Subject
- time-trial completion time
- Findings
- 7
- Papers
- 7
Dose-Response Effect of Oral Caffeine Use on Aerobic Exercise Performance: A Systematic Review and Meta-Analysis.record2026PMID:423563751 finding
The Effects of Astaxanthin Supplementation on Exercise Recovery Biomarkers and Exercise Performance: A Systematic Review and Meta-Analysis.record2026PMID:421970301 finding
Short-Term Magnesium Supplementation Has Modest Detrimental Effects on Cycle Ergometer Exercise Performance and Skeletal Muscle Mitochondria and Negligible Effects on the Gut Microbiota: A Randomized Crossover Clinical Trial.record2025PMID:400777841 finding
Caffeine, CYP1A2 Genotype, and Endurance Performance in Athletes.record2018PMID:295096411 finding
Caffeine increases performance in cross-country double-poling time trial exercise.record2013PMID:235912941 finding
Dose response of caffeine on 2000-m rowing performance.record2010PMID:199528221 finding
Enhancement of 2000-m rowing performance after caffeine ingestion.record2000PMID:110795281 finding