Influence of Resistance Training Experience and Mental Imagery on Corticospinal Excitability and Inhibition
Condition: Resistance Training
Study type: Interventional

Summary: 
      This study will utilize transcranial magnetic stimulation (TMS) to examine the effects of
      mental imagery in resistance-trained versus untrained men and women. In randomized order,
      each participant will perform a mental imagery task or a control condition as TMS is used to
      study corticospinal excitability.
    

Detailed description: 
      Kinesthetic mental imagery is a technique that has previously been utilized to modulate
      neural signaling to the limbs in the absence of any mechanical movement of the limb.
      Kinesthetic imagery tasks require an individual to imagine they are maximally contracting a
      target muscle group. Previous investigations have shown mental imagery tasks to increase
      maximal strength of the limb and even attenuate strength loss during periods of
      immobilization. Similarly, corticospinal excitability, which indicates the ease in which the
      cortex can stimulate muscular contraction, has also been shown to increase during mental
      imagery tasks. These adaptations have been attributed to the role of the cortex as a critical
      determinant of strength and the potent cortical stimulus posed by mental imagery.

      Mental imagery and resistance training have both shown to provide a positive impact on muscle
      strength. However, the interplay between a mental imagery task and resistance training
      experience has yet to be fully investigated in terms of their impact on corticospinal
      excitability and inhibition. To our knowledge, no study has examined the effect of resistance
      training experience on corticospinal excitability and inhibition during a mental imagery
      task. Thus, the purpose of this study is to determine if resistance trained and untrained
      participants experience differences in corticospinal excitability and inhibition during
      kinesthetic mental imagery.
    

Intervention name(s): Mental Imagery
Intervention type(s): Other
Intervention description(s): Immediately after determination of the resting motor threshold and pre-test measurements, the TMS administrator will leave the room so as to be blinded to the treatment condition of the participant. At this time the participant will be given instructions regarding the mental imagery protocol from a separate investigator who will not be blinded to the condition. During the mental imagery protocol, participants will be instructed to close their eyes and imagine they are maximally contracting the muscles in their forearm and imagine that they are making their wrist flex and that they are pushing maximally against a hand grip in their hand. This will be a kinesthetic imagery task, in which they are urging their muscles to contract maximally.
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Within-subjects design with mental imagery and control conditions performed in random order
Masking: Single (Outcomes Assessor)
Primary purpose: Basic Science