RCTJadad 2/5RandomizedDouble-BlindPlacebo-Controlled

Test Title

Scientific ReportsMarch 26, 2026Vol. 16

PubMed DOI

Summary

Test summary.

What This Means For You

Test implications.

Important Considerations

Test caveats.

Terms Explained

Technical Study Details

Study Design

Duration2 weeks

Total Score

JADAD Quality Assessment

/ 5

評価詳細

Randomization

0 / 2

Is the study described as randomized?

Yes+1

Rationale: The article explicitly and repeatedly describes the study as randomized, including "were randomized into four groups," "A randomized, double-blind, placebo-controlled design was utilized," and "double-blind, randomized, placebo-controlled design" in the methods, as well as "This randomized, placebo-controlled study" in the conclusion.

Is the method of randomization described and appropriate?

No-1

Rationale: The article repeatedly states that participants were "randomized" and describes a "randomized, double-blind, placebo-controlled design," but nowhere does it specify the actual method used to generate the randomization sequence (e.g., computer-generated random numbers, random number tables, coin toss). Since the specific randomization method is not described anywhere in the Methods, Participants, or Supplementation protocol sections, this criterion cannot be judged as appropriate — per the Jadad scale, an unspecified method scores "no" (only stating "randomized" without describing the method).

Blinding

2 / 2

Is the study described as double-blind?

Yes+1

Rationale: The article explicitly and repeatedly describes the study design as "double-blind" in the Introduction, Methods (Supplementation protocol), and Data Availability sections, satisfying the criterion for Q3.

Is the method of blinding described and appropriate?

Yes+1

Rationale: The article explicitly describes the double-blinding method: solutions were prepared in opaque, coded bottles by an independent researcher not involved in data collection, and a non-caloric lemon flavoring agent was added to all solutions (creatine, protein, and placebo) to mask sensory differences. The placebo used xylitol solution specifically chosen to mimic the sweetness and texture of the active supplements. This constitutes an appropriate blinding method, as it addresses matching appearance/taste/texture across all groups to prevent participants and researchers from distinguishing treatment allocation.

Dropouts/Withdrawals

0 / 1

Is there a description of dropouts and withdrawals?

No0

Rationale: The article states that 60 participants were recruited and randomized into four groups of 15, and reports statistical analyses presumably based on all 60. However, nowhere in the Methods, Results, or Discussion sections is there any mention of withdrawals, dropouts, participant attrition, or the number of participants who completed the study versus were enrolled. No reasons for any loss of participants are given, and no per-group final analyzed sample sizes are reported distinct from the initial randomization numbers. Therefore this criterion is not met.

Study Population

Sample Size60

Age RangeMean: 21 years

ConditionAnaerobic exercise performance / repeated Wingate sprint capacity in healthy physically active males

Inclusion Criteria

Healthy, physically active male university students
No formal association with sports majors

Interventions

Creatine monohydrate

Treatment

Dose0.3 g/kg/day total (0.075 g/kg per dose)

Frequency4 divided doses daily at 4-hour intervals

Duration4 days

Routeoral

Carbohydrate (glucose) - CRCHO regimen

Treatment

Dose1.0 g/kg/day total (0.25 g/kg per dose)

Frequency4 divided doses daily

Duration4 days

Routeoral

Carbohydrate (glucose) - CRCPS regimen

Treatment

Dose0.8 g/kg/day total (0.2 g/kg per dose)

Frequency4 divided doses daily

Duration4 days

Routeoral

Whey protein isolate

Treatment

Dose0.2 g/kg/day total (0.05 g/kg per dose)

Frequency4 divided doses daily

Duration4 days

Routeoral

Placebo (xylitol solution)

Control

Frequency4 divided doses daily

Duration4 days

Routeoral

Outcomes

Outcome	Type	Effect	p-value
Absolute Mean Power	Primary	-	p < 0.01Significant
Relative Mean Power	Primary	-	p < 0.01Significant
Absolute Peak Power	Secondary	-	p < 0.01Significant
Relative Peak Power	Secondary	-	p < 0.01Significant
Blood Lactate Concentration	Secondary	-	p < 0.01Significant
Body Mass	Secondary	-	p < 0.01 (overall interaction); p = 0.026 for CRSignificant

Safety

No adverse events, dropouts, or discontinuations were reported in the article.

Conclusion

Both CRCHO (creatine + carbohydrate) and CRCPS (creatine + carbohydrate + protein) supplementation for four days improved absolute and relative mean power output across three consecutive Wingate sprints compared to baseline, whereas the placebo group showed performance decrements in later trials. All supplementation groups (CR, CRCHO, CRCPS) improved absolute and relative peak power across trials, while placebo only improved in the third trial. CRCPS produced the highest post-exercise blood lactate concentrations, suggesting enhanced glycolytic contribution. No statistically significant direct comparison was found between CRCHO and CRCPS, but the pattern suggests a possible additive benefit of protein co-ingestion. Combined creatine-carbohydrate-protein supplementation may help mitigate fatigue and enhance mean power output during repeated high-intensity anaerobic efforts more effectively than placebo.

Limitations

Modest sample size (60 participants across four groups)
Lack of strict dietary monitoring beyond self-reported logs
Short intervention duration (4-day loading protocol)
No direct statistical comparisons between all active supplementation groups (e.g., CRCHO vs CRCPS), limiting conclusions about a genuine synergistic protein effect