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Study note

Whey or Casein Hydrolysate with Carbohydrate for Metabolism and Performance in Cycling.

PMID 25941925 (2015): carbohydrate, carb — Time to exhaustion, Time-trial performance, Fat oxidation (study note for endurance athletes).

Updated Feb 23, 2026

Read the study note

Study note • PMID 25941925

Whey or Casein Hydrolysate with Carbohydrate for Metabolism and Performance in Cycling.

International journal of sports medicine2015 • DOI 10.1055/s-0034-1398647

How to use this page

This note summarizes one study record. Check the participants, methods, results, and limitations before applying it to training.

  • Design signal: randomized trial.
  • Population relevance: mixed/unclear athlete specificity.
  • Consistency: single-study evidence.
  • Practical recommendation depends on tolerance, context, and whether it protects training consistency.

ELI5

In plain language

The protein type most suitable for ingestion during endurance exercise is undefined. (randomized trial; cyclists).

Effects on Time-trial performance, Fat oxidation are mixed or unclear from the abstract alone. Treat this as a signal, not a guarantee; confirm methods and context in the full paper.

Takeaways

What the abstract suggests

  • Study question: The protein type most suitable for ingestion during endurance exercise is undefined.
  • Effects on Time-trial performance, Fat oxidation are mixed or unclear from the abstract alone.
  • Population: cyclists.
  • Protocol cues (title/abstract): 2 h.

Protocol

Protocol (as reported)

  • Intervention/exposure: carbohydrate, carb (vs placebo).
  • Dose/time/duration cues in abstract/title: 2 h.
  • Outcomes: Time to exhaustion, Time-trial performance, Fat oxidation.
  • Replication note: abstracts often omit adherence and timing; confirm details before changing training or supplementation.

Fit

Who it may help, and who should be cautious

Who it helps

  • Athletes similar to the study population (cyclists) working on fueling.
  • Athletes who can measure Time to exhaustion, Time-trial performance, Fat oxidation with a repeatable workout or time-trial effort.

Who should be cautious

  • If you have symptoms or conditions that make the intervention risky, get professional guidance.
  • If you’re near race day and can’t safely test, defer the experiment.

Methods

What the study actually did

  • Design: randomized trial (double-blind, placebo-controlled).
  • Population: cyclists.
  • Comparator: placebo.
  • Outcomes measured: Time to exhaustion, Time-trial performance, Fat oxidation.
  • Protocol cues mentioned: 2 h.
  • Source: PubMed PMID 25941925 (2015) — International journal of sports medicine.

Results excerpt

What the abstract reports

However, neither protein hydrolysate enhanced time trial performance when compared with carbohydrate-only.

Note: excerpts are short; for full context, read the paper.

Limits

Limitations and bias

  • Abstract-only summaries can miss critical details (population, protocol, adherence, and context).
  • Single studies often don’t generalize to your event, history, and training load; treat results as a starting point.
  • If your context differs (elite vs recreational; cycling vs running), adjust expectations and be conservative.
  • This is performance information, not medical advice.

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