235 Effects of three days magnesium supplementation on anaerobic exercise performance

Abstract

Magnesium is reportedly important in energy production and therefore may play a role in both anaerobic and aerobic performance. Therefore, this study investigated the effects of dietary magnesium supplementation on repeated, anaerobic cycling performance. Thirteen (8 male, 5 female) healthy, active volunteers provided written informed consent to participate in the study (mean and range age, height and mass of 21 yr, 17-40 yr; 177.0 cm, 161.0-190.2 cm; 71.7 kg, 51.3-96.2 kg). A randomised, double-blind, placebo-controlled procedure was employed whereby the participants were tested at the same time of day, 7 d apart following 3 d supplementation with a commercially-available magnesium supplement (122 mg/d magnesium) or the equivalent dose of a placebo. Testing involved a 5 min warm up followed by two 60 s maximal cycling efforts separated by 3 min rest. Peak power, time to reach peak power, total work, rating of perceived exertion (RPE) and maximal HR were assessed during each exercise bout. Blood lactate was assessed at rest, following bout 1 and at 3 and 5 min after bout 2. Peak power, time to peak power, work and maximal HR all significantly decreased and RPE significantly increased from bout 1 to bout 2. However, magnesium supplementation did not significantly alter any of the measured variables during either exercise bout when compared to the placebo. Resting, mid-exercise and peak post-exercise lactates were also not affected by magnesium supplementation compared to the placebo. In conclusion, 3 d dietary magnesium supplementation did not enhance anaerobic exercise performance or recovery between bouts.