Running 8000 m fast or slow: Are there differences in energy cost and fat metabolism?

TitelRunning 8000 m fast or slow: Are there differences in energy cost and fat metabolism?
MedientypJournal Article
Year of Publication2005
AutorenRosenberger F, Meyer T, Kindermann W
JournalMed Sci Sports Exerc
Date Published2005 Oct
SchlüsselwörterAdipose Tissue, Calorimetry, Indirect, Energy Metabolism, Female, Heart Rate, Humans, Lactic Acid, Male, Pulmonary Gas Exchange, Running

PURPOSE: To compare energy requirements and substrate use for running a given distance fast versus slow under field conditions.

METHODS: Ten males and four females who were moderately endurance trained (32 +/- 6 yr; 71 +/- 11 kg; body mass index: 22.7 +/- 2.3 kg x m(-2); VO2max: 62.0 +/- 6.0 mL x min(-1) x kg(-1); individual anaerobic threshold [IAT]: 13.7 +/- 1.4 km x h(-1)) performed an incremental running protocol to determine IAT. Subsequently, two 8000-m runs at 70 and 95% IAT were performed on separate days in randomized order on an indoor track. Energy expenditure (EE) was measured by means of a portable metabolic device (indirect calorimetry). A meaningful difference in EE was defined as >10%.

RESULTS: EE was significantly greater during the 95% IAT run than during the 70% IAT run (2650 +/- 276 and 2554 +/- 348 kJ, respectively). However, this difference was only 3.8 +/- 4.8%. Including measurements up to 10 min postexercise, the difference rose to 5.1 +/- 4.7% (95% IAT: 2830 +/- 301 kJ; 70% IAT: 2692 +/- 368 kJ). There was no significant difference between the absolute amounts of fat oxidized during the runs (70% IAT: 26 +/- 5 g; 95% IAT: 20 +/- 5 g). During the 95% IAT run, significantly more carbohydrates were metabolized than during the 70% IAT run (108 +/- 14 and 90 +/- 5 g, respectively). The difference in EE between the two runs increased from the first to the third part of the running distance (first: no significance; second: P < 0.01; third: P < 0.001).

CONCLUSION: Energy requirements for a commonly run distance in recreational endurance training differ significantly but not relevantly between slow and fast speeds. However, increasing total running distance might lead to larger differences.

Alternate JournalMed Sci Sports Exerc
PubMed ID16260982
Nicht definiert