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The Reliability of Fat max
Author(s) -
Meyer T.,
Folz C.,
Rosenberger F.,
Kindermann W.
Publication year - 2009
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/j.1600-0838.2008.00775.x
Subject(s) - zoology , medicine , limits of agreement , respiratory exchange ratio , vo2 max , blood lactate , reproducibility , nuclear medicine , mathematics , heart rate , biology , blood pressure , statistics
The exercise intensity eliciting maximal fat oxidation (Fat max ) is typically determined during an incremental test. Its reproducibility, however, has not been thoroughly investigated so far. To address this issue, 21 healthy subjects (23.5±1.7 years; BMI 22.4±1.8 kg/m 2 ; VO 2peak 47.4±11.3 mL/min/kg) carried out two identical cycling tests to determine Fat max after an initial incremental baseline test. The duration of each of five stages during the Fat max tests was 6 min. The first stage equalled the first increase in blood lactate during the baseline test; the highest stage corresponded to a respiratory exchange ratio of 1.00. Between these intensities the other three stages were distributed evenly. Fat max was 28.0±8.6 L/min (59.2±18.1% VO 2peak ) in the first test and 29.8±10.5 L/min (62.9±22.2% VO 2peak ) in the second one. There was no significant difference between both Fat max determinations [number of stage: P =0.31; total VO 2 : P =0.20; VO 2 utilized for fat oxidation (VO 2Fat ): P =0.33]. Linear correlation coefficients between tests were r =0.84 (total VO 2 ; P <0.001) and r =0.83 (VO 2Fat ; P <0.001). However, Bland–Altman plots revealed wide 95% limits of agreement of 0.91 L/min (total VO 2 ) and 0.32 L/min (VO 2Fat ). In conclusion, spontaneous intraindividual variability in Fat max appears too large to recommend the use of this parameter for the prescription of training intensity.