Description:
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<jats:title>Background</jats:title>
<jats:p>Studies on motor imagery (MI) practice based on different designs and training protocols have reported changes in maximal voluntary contraction (MVC) strength. However, to date, there is a lack of information on the effects of MI training on contractile properties of the trained muscle.</jats:p>
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<jats:title>Methods</jats:title>
<jats:p>Forty-five physically active sport science students (21 female) were investigated who trained three times per week over a 4-week period in one of three groups: An MI group conducted MI practice of maximal isometric contraction of the biceps brachii; a physical exercise (PE) group physically practiced maximal isometric contractions of the biceps brachii in a biceps curling machine; and a visual imagery (VI) group performed VI training of a landscape. A MVC test of the arm flexors was performed in a biceps curling machine before and after 4 weeks of training. The muscular properties of the biceps brachii were also tested with tensiomyography measurements (TMG).</jats:p>
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<jats:title>Results</jats:title>
<jats:p>Results showed an interaction effect between time and group for MVC (<jats:italic>p</jats:italic> = 0.027, <jats:italic>η</jats:italic><jats:sup>2</jats:sup> = 0.17), with a higher MVC value in the PE group (Δ5.9%) compared to the VI group (Δ −1.3%) (<jats:italic>p</jats:italic> = 0.013). MVC did not change significantly in the MI group (Δ2.1%). Analysis of muscle contractility via TMG did not show any interaction effects neither for maximal radial displacement (<jats:italic>p</jats:italic> = 0.394, <jats:italic>η</jats:italic><jats:sup>2</jats:sup> = 0.05), delay time (<jats:italic>p</jats:italic> = 0.79, <jats:italic>η</jats:italic><jats:sup>2</jats:sup> = 0.01) nor contraction velocity (<jats:italic>p</jats:italic> = 0.71, <jats:italic>η</jats:italic><jats:sup>2</jats:sup> = 0.02).</jats:p>
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<jats:title>Conclusion</jats:title>
<jats:p>In spite of MVC-related changes in the PE group due to the interventions, TMG measurements were not sensitive enough to detect concomitant neuronal changes related to contractile properties.</jats:p>
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