The efficacy of Farabloc, an electromagnetic shield, in attenuating delayed-onset muscle soreness

Objective: To assess the hypothesis that Farabloc, a fabric with electromag netic shielding properties, would attenuate the symptoms, signs, and muscul ar strength deficit secondary to delayed-onset muscle soreness (DOMS) induc ed by two exposures to eccentric exercise in humans. Design: Randomized, single-blind, placebo-controlled, crossover trial with two testing stages of 5 days duration separated by a washout period of more than 8 weeks. Setting: University-based sports medicine center. Participants: Twenty volunteers equally representing untrained male and fem ale subjects. Interventions: 20 sets of 10 repetitions of single-leg eccentric knee exten sions for 37 minutes with the Biodex dynamometer set at 30 degrees per seco nd were performed on the first day of stage one and stage two to induce DOM S in the quadriceps muscle. Double layers of fabric, either Farabloc or pla cebo, were wrapped around the thigh of each participant during each stage f or 5 days. Main Outcome Measures: Perception of muscle pain, as measured by a visual a nalog scale (VAS), and strength, as measured by knee extensor torque (EST) with the Biodex dynamometer, were evaluated at 0, 24, 48, 72, and 96 hours. Serum inflammatory markers of muscle damage, including malondialdehyde, cr eatine phosphokinase, myoglobin, leukocytes, and neutrophils, were assayed at 0, 2, 6, 24, and 48 hours. Results: Repeated-measures analysis of variance was carried out for each of the seven variables to assess differences for fabric, order of treatment, time, and all combinations. Results of VAS and EST and levels of malondiald ehyde, creatine phosphokinase, myoglobin, leukocytes, and neutrophils all s howed a highly significant effect of Farabloc compared with placebo. This a nalysis shows that the order of Farabloc or placebo fabric use in stage 1 a nd 2 produces different results. This may be caused by a learning effect, b ut did not alter the overall influence of Farabloc. Conclusion: The data indicate that double layers of Farabloc fabric wrapped around the thigh reduces pain and strength loss and serum levels of malond ialdehyde, creatine phosphokinase, myoglobin, leukocytes, and neutrophils w hen untrained human subjects are exposed to eccentric exercise to produce D OMS in the quadriceps. Farabloc shields high-frequency electromagnetic fiel ds, although the results do not indicate how these changes are mediated. Fu rther research is needed to determine the mechanism.