To establish whether the MVC testing that was of the experimental protocal contributed to the experimental protocol contributed to force gains, a control group was usd. These subjects performed MVCs 6 times per day for 19 day to match the experimental group, who performed 3 MVCs before each stimulation session and 3 MVCs after each stimulation session. No increase in force was produced. Although this finding demonstrates that the force gains were not a result of performing repetitive MVCs, the control group does not control for a placebo response, because there is no way the controls could be unaware of the presence or absence of electrical stimulation. Given that few of the later studies by a variety of authors showed such large force gains with stimulation sessions so few and short, we guestion whether the extreme motivation for the young Russian athletes was a factor in the force gains.possibly the age of the subjects had a bearing on the outcome.other studies (reviewed by Selkowitz) used subjects who were more physically mature and less motivated.
Medium-Frequency Alternating Current
Andrianova et al reported on the use of kilohertzfrequency sinusoidal altrenating current for increasing a muscle's
force-generating capability. Both continuous (unmodulated) AC and AC bursts, modulated at 50 Hz (10 milliseconds "on" and 10 milliseconds"off"), were used. Andrianova and colleagues examined "direct" stimulation, where the electrodes were placed over the muscle, and "indirect" stimulation, where they attempted to stimulate the nerve trunk supplying the muscle. Their article reports a 4-part study involving either wrist and finger flexors or the calf muscles, or both. For direct stimulation of wrist and finger flexors electrodes measuring 6×3 cm and 4×3 cm were applied to the palmar surface of the forearm, with the long side across the forearm and the larger electrode more proximal. For indirect stimulation, a thin electrode (2.5×0.5 cm) was positioned along the fissure of the elbow joint and a larger electrode (3×1.5 cm or 3.5×1 cm, respectively) was position on the palmar surface of the forearm or on the inner surface of the shoulder (long side across the inner surface).No further details of eletrode placement were given. the authors stated that the same size electrode placement were given. It is uncertain, therefore, how electrodes were located to activate the nerve trunk supplying the calf muscle. the number of subjectsin each part of the study ranged from 7 to 10
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