Mean (±SE) isometric muscle strength measurements [handgrip strength, lower-extremity (LE) muscle power, knee extension torque, and ankle extension isometric strength] according to serum magnesium concentrations. Tertile 1 is the lowest tertile, tertile 2 is the intermediate, and tertile 3 is the highest. To convert mg/dL to mmol/L, multiply by 0.411. Bars with different letters are significantly different, P < 0.05 (ANOVA followed by Tukey’s multiple-comparisons test). P values in the figure correspond to P for trend.