This study investigated the effects of dietary magnesium (Mg) on strength development during a double-blind, 7-week strength training program in 26 untrained subjects (14 = control, C and 12 = Mg supplemented, M), 18-30 years old. Subjects' 3-day diet records were analyzed and Mg content was calculated. C received a placebo and M received a supplement (Mg oxide) to bring Mg intake, including diet, to 8 mg/kg body weight/day. Body composition was assessed with bioelectrical impedance. Pre and post quadriceps torque (T) measurements were made with an Orthotron at 120 deg/sec. Each subject performed three sets of 10 reps, leg press and leg extension, three times/week. Both groups gained strength, however, results indicated a significant (p less than 0.05) increase for the M group compared to the C group in absolute T, relative T adjusted for body weight (T/BWT), and relative T adjusted for lean body mass (T/LBM) when pre values were used as the covariate. M was consistently greater than C (T: 211 vs 174 Nm; T/BWT: 3.07 vs 2.58 Nm/kg; T/LBM: 3.84 vs 3.36 Nm/kg).
Conclusion: Significant differences in T gains after strength training were demonstrated in M vs C. Mg's role may be at the ribosomal level in protein synthesis.