The efficacy of Farabloc, an electromagnetic shield, in attenuating delayed-onset muscle soreness.
OBJECTIVE
To assess the hypothesis that Farabloc, a fabric with electromagnetic shielding properties, would attenuate the symptoms, signs, and muscular strength deficit secondary to delayed-onset muscle soreness (DOMS) induced by two exposures to eccentric exercise in humans.


METHODS
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.


METHODS
University-based sports medicine center.


METHODS
Twenty volunteers equally representing untrained male and female subjects.


METHODS
20 sets of 10 repetitions of single-leg eccentric knee extensions for 37 minutes with the Biodex dynamometer set at 30 degrees per second were performed on the first day of stage one and stage two to induce DOMS in the quadriceps muscle. Double layers of fabric, either Farabloc or placebo, were wrapped around the thigh of each participant during each stage for 5 days.


METHODS
Perception of muscle pain, as measured by a visual analog 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. creatine 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 malondialdehyde, creatine phosphokinase, myoglobin, leukocytes, and neutrophils all showed a highly significant effect of Farabloc compared with placebo. This analysis shows that the order of Farabloc or placebo fabric use in stage I and 2 produces different results. This may be caused by a learning effect, but did not alter the overall influence of Farabloc.


CONCLUSIONS
The data indicate that double layers of Farabloc fabric wrapped around the thigh reduces pain and strength loss and serum levels of malondialdehyde, creatine phosphokinase, myoglobin, leukocytes, and neutrophils when untrained human subjects are exposed to eccentric exercise to produce DOMS in the quadriceps. Farabloc shields high-frequency electromagnetic fields, although the results do not indicate how these changes are mediated. Further research is needed to determine the mechanism.
Zhang
J
J
Allan McGavin Sports Medicine Centre, School of Human Kinetics, University of British Columbia, Vancouver, Canada.
Clement
D
D
Taunton
J
J
D000328:Adult; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D003402:Creatine Kinase / Q000097:blood; D018592:Cross-Over Studies; D004574:Electromagnetic Fields; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D007958:Leukocyte Count; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009211:Myoglobin / Q000097:blood; D009504:Neutrophils / Q000473:pathology; D010146:Pain / Q000503:physiopathology / Q000517:prevention & control*; D010147:Pain Measurement; D005082:Physical Exertion / Q000502:physiology*; D010919:Placebos; D011835:Radiation Protection / Q000295:instrumentation*; D016059:Range of Motion, Articular / Q000502:physiology; D016037:Single-Blind Method; D019415:Torque
D015415:Biomarkers; D009211:Myoglobin; D010919:Placebos; D008315:Malondialdehyde; D003402:Creatine Kinase