Predicting the ergogenic response to methylphenidate
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Methylphenidate (MPH) and other stimulants have been shown to enhance physical performance. However, stimulant research has almost exclusively been conducted in young, active persons with a normal BMI, and may not generalize to other groups. The purpose of this study was to determine whether the ergogenic response to MPH could be predicted by individual level characteristics.
We investigated whether weekly minutes of moderate-to-vigorous physical activity (MVPA), age, and BMI could predict the ergogenic response to MPH. In a double-blind, cross-over design 29 subjects (14M, 15F, 29.7 ± 9.68 years, BMI: 26.1 ± 6.82, MVPA: 568.8 ± 705.6 min) ingested MPH or placebo before performing a handgrip task. Percent change in mean force between placebo and MPH conditions was used to evaluate the extent of the ergogenic response.
Mean force was significantly higher in MPH conditions [6.39% increase, T(25) = 3.09, p = 0.005 118.8 ± 37.96 (± SD) vs. 111.8 ± 34.99 Ns] but variable (coefficient of variation:163%). Using linear regression, we observed that min MVPA (T(25) = −2.15, β = −0.400, p = 0.044) and age [T(25) = −3.29, β = −0.598, p = 0.003] but not BMI [T(25) = 1.67, β = 0.320 p = 0.109] significantly predicted percent change in mean force in MPH conditions.
We report that lower levels of physical activity and younger age predict an improved ergogenic response to MPH and that this may be explained by differences in dopaminergic function. This study illustrates that the ergogenic response to MPH is partly dependent on individual differences such as habitual levels of physical activity and age.
KeywordsErgogenic stimulants Athletic performance Athletic doping Ritalin
Author contributions statement
The roles of the authors were as follows: MK: conception, data acquisition, design, interpretation, and drafting, KVB: data acquisition and drafting, DS: interpretation and drafting, KL: analysis, interpretation, and drafting, and HGLR: interpretation and drafting.
We acknowledge our funding contributions: National Research Foundation and Novartis South Africa.
Compliance with ethical standards
Conflict of interest
Novartis did not influence study design, data collection, analysis, interpretation, writing, or decision to submit the article for publication. No authors were paid by Novartis.
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