The effect of flexible magnets on hand muscle strength: a randomized, double-blind study

The purpose of this study was to determine the effect of a flexible magnet on hand grip and thumb-forefinger pinch strength. Flexible magnet use has become popular in sports medicine and rehabilitation for a number of reasons, including augmenting muscle force output. Thirty-five university students (18 men and 17 women) volunteered for this study. Each subject was tested for grip strength (grip dynamometer) and thumb-forefinger pinch strength (pinch gauge) under 3 different treatment conditions: baseline (no magnet), sham magnet (placebo), and flexible magnet (700-G intensity). The order of treatments was randomly assigned, and all data collection followed a double-blind format. For grip strength measurements, magnet placement was over the bellies of the flexor digitorum profundus and flexor digitorum superficialis, and for pinch strength measurements, it was over the bellies of the flexor pollicis brevis and opponens pollicis. Three trials for each strength measurement for each of the 3 conditions were performed. Magnets (700 G or sham) were placed on the appropriate areas of the skin 3 minutes before the first test trial, with each subsequent test trial separated by 1 minute. Comparison among the 3 treatment conditions was analyzed using a 1-way analysis of variance (ANOVA) with repeated measures. ANOVA revealed no statistically significant (p > 0.05) mean differences for strength among any of the 3 treatments (baseline, 700-G magnet, or sham magnet) for either hand grip or thumb-forefinger pinch within each sex subgroup or for the combined group. The findings indicate that flexible magnets with a field strength of 700 G do not increase muscle strength.