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Study note

Carbohydrate-gel supplementation and endurance performance during intermittent high-intensity shuttle running.

PMID 18046054 (2007): carbohydrate, carb — Time to exhaustion, Time-trial performance, Fat oxidation (study note for endurance athletes).

Updated Jul 22, 2026

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Study note • PMID 18046054

Carbohydrate-gel supplementation and endurance performance during intermittent high-intensity shuttle running.

International journal of sport nutrition and exercise metabolism • 2007 • DOI 10.1123/ijsnem.17.5.445
Open on PubMed

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 aim of this study was to investigate the effects of a carbohydrate (CHO) gel on performance after prolonged intermittent high-intensity shuttle running. (randomized trial; participants).

The abstract suggests a positive effect on Time to exhaustion, Time-trial performance under the tested conditions. Treat this as a signal, not a guarantee; confirm methods and context in the full paper.

Takeaways

What the abstract suggests

  • • Study question: The aim of this study was to investigate the effects of a carbohydrate (CHO) gel on performance after prolonged intermittent high-intensity shuttle running.
  • • The abstract suggests a positive effect on Time to exhaustion, Time-trial performance under the tested conditions.
  • • Population: participants.
  • • Protocol cues (title/abstract): 15 min • 60 min • 1.3 min • 1.2 min.

Protocol

Protocol (as reported)

  • • Intervention/exposure: carbohydrate, carb (vs placebo).
  • • Dose/time/duration cues in abstract/title: 15 min • 60 min • 1.3 min • 1.2 min.
  • • 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 (participants) 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 (placebo-controlled).
  • • Population: participants.
  • • Comparator: placebo.
  • • Outcomes measured: Time to exhaustion, Time-trial performance, Fat oxidation.
  • • Protocol cues mentioned: 15 min • 60 min • 1.3 min • 1.2 min.
  • • Source: PubMed PMID 18046054 (2007) — International journal of sport nutrition and exercise metabolism.

Results excerpt

What the abstract reports

“During Part B, run time to exhaustion was longer (P < 0.05) in the CHO trial (CHO 6.1 +/- 1.3 min vs.”

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.

What this gel study does and does not answer

This randomized trial tested carbohydrate gel during prolonged intermittent high-intensity shuttle running, then measured a run-to-exhaustion outcome. It is not a marathon, triathlon or 100K field trial, and time to exhaustion is not the same as a finish-time benefit.

The practical use is narrower: carbohydrate form and timing can be tested during a session that resembles the athlete's expected duration and intensity. Rehearse one familiar product, record dose, fluid, gastrointestinal response and the rest of that day's intake, and change one variable at a time.

Read the complete methods in the PubMed record before copying the protocol. A positive group result does not establish tolerance, medical suitability or the right amount for an individual. Avoid new gels, large dose jumps or untested caffeine combinations on race day.

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Performance Science Lab

Research summaries for endurance athletes, with study context, practical protocols, and clear limitations.

Fueling performance research

Fueling is performance, not just health: the right carbs at the right time change outcomes.

Time to exhaustion research for endurance athletes

A lab outcome that can still guide training: it often tracks fatigue resistance.

Sources