Affiliations: [a] Department of Kinesiology and Health, | [b] Head Athletics Trainer, | [c] Department of Physical Therapy and | [d] Department of Educational Policy Studies, Georgia
State University, Atlanta, GA 30303, USA
Note: [] Georgia State University, Dept of Kinesiology and Health,
University Plaza, Atlanta, GA 30303, USA. Tel.: +1 404 651 4022; Fax: +1 404
651 4814; E-mail: ltis@gsu.edu
Abstract: The purpose of this study was to determine the effects of magnets on
concentric and eccentric isokinetic peak and average force production of the
dominant knee extensor musculature. All subjects were randomly assessed via
isokinetic dynamometry (KinCom 500H, Chattecx Corp.) for concentric and
eccentric peak and average force production of the quadriceps in the conditions
of magnet, placebo magnet, and control (no magnet). Subjects were assessed at
test velocities of 60 and 120
^{\circ}/s.
Twenty-one subjects (age = 24.2 + 5.1 yrs, ht =
174.6 + 8.2 cm, wt = 73 + 6.9 kg) voluntarily
participated in the study. Subjects were excluded if they reported a history of
knee surgery or sustained a knee injury within the past six months. Two
three-way MANOVA's (velocity \times mode
\times treatment) were used to determine differences between
variables. MANOVA revealed significant differences between test velocities
(p<0.001) and mode of contraction p<0.05)
for peak force production and significant differences between test velocities
(p<0.05) and mode of contraction
(p<0.001) for average force production. MANOVA revealed a
significant difference between testing conditions for average force production
(p<0.05). However, Tukey's post-hoc analysis found no
significant difference between conditions. Based on the results of this study,
application of a magnetic pad to the quadriceps muscles does not appear to
increase acute force production. Further research is needed to critically
evaluate other purported effects of magnetotherapy.
Keywords: magnetotherapy, strength, biomagnetics, alternative therapy
