DOES THE IMAGINED CONTRACTION SPEED DURING MOTOR IMAGERY AFFECT ACUTE MUSCLE FUNCTION?

Disciplines

Kinesiotherapy | Physiotherapy

Abstract (300 words maximum)

DOES THE IMAGINED CONTRACTION SPEED DURING MOTOR IMAGERY AFFECT ACUTE MUSCLE FUNCTION?

Caleb Offutt, Kayla Anderson, Anna Acosta, Lacey Harper Kaden Buford, Rachel Carlstrom, Garrett Hester

Department of Exercise Science and Sport Management, Kennesaw State University

Everyone except Rachel is out of ESSM. Rachel is out of Biology.

Background: Research indicates that a single session of imaginary muscle contractions (aka motor imagery; MI) acutely increases strength. This work is limited to generic instructions, so it is unclear whether speed (i.e., fast vs. slow) of imagined contractions affects acute muscle function responses. Purpose: To determine the acute effects of fast and slow imagined muscle contractions on maximal and rapid muscle force production. Methods: As part of an ongoing study, seven young (18-30 yrs) adults completed 3 experimental visits in randomized order after completing a familiarization visit. Experimental visits included a control (seated quietly), fast MI condition, and slow MI condition. During fast MI, subjects were instructed to imagine pulling with their bicep “as fast and hard as possible, whereas the instruction was to imagine “gradually increasing force for 3 sec until you are pulling as hard as possible” for the slow condition. Two blocks of 25 imagined muscle contractions separated by 1 min of rest were completed. Before and after each condition, subjects performed rapid, maximal isometric contractions of the elbow flexors with a dynamometer. Peak torque (maximal strength) and rate of torque development (explosiveness) were calculated from the torque-time curve data. Peak torque was considered the highest rolling 500 ms average, whereas RTD was determined from the slope of the torque-time curve from contraction onset to 50, 100, and 200 ms. A Wilcoxon test was used to examine changes within each condition. Results: Peak torque (p=0.63 – 0.612) nor any RTD outcomes (p=0.091- 0.866) changed following either condition. Conclusions: Our preliminary results suggest a potential small effect of fast MI on PT (+4%; p = 0.063), albeit not statistically significant, whereas RTD outcomes remained constant. As we recruit a larger sample size, a more powerful analysis will yield stronger evidence regarding the effects, if any, of different types of MI on acute muscle function.

Academic department under which the project should be listed

WCHHS - Exercise Science and Sport Management

Primary Investigator (PI) Name

Garrett Hester

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DOES THE IMAGINED CONTRACTION SPEED DURING MOTOR IMAGERY AFFECT ACUTE MUSCLE FUNCTION?

DOES THE IMAGINED CONTRACTION SPEED DURING MOTOR IMAGERY AFFECT ACUTE MUSCLE FUNCTION?

Caleb Offutt, Kayla Anderson, Anna Acosta, Lacey Harper Kaden Buford, Rachel Carlstrom, Garrett Hester

Department of Exercise Science and Sport Management, Kennesaw State University

Everyone except Rachel is out of ESSM. Rachel is out of Biology.

Background: Research indicates that a single session of imaginary muscle contractions (aka motor imagery; MI) acutely increases strength. This work is limited to generic instructions, so it is unclear whether speed (i.e., fast vs. slow) of imagined contractions affects acute muscle function responses. Purpose: To determine the acute effects of fast and slow imagined muscle contractions on maximal and rapid muscle force production. Methods: As part of an ongoing study, seven young (18-30 yrs) adults completed 3 experimental visits in randomized order after completing a familiarization visit. Experimental visits included a control (seated quietly), fast MI condition, and slow MI condition. During fast MI, subjects were instructed to imagine pulling with their bicep “as fast and hard as possible, whereas the instruction was to imagine “gradually increasing force for 3 sec until you are pulling as hard as possible” for the slow condition. Two blocks of 25 imagined muscle contractions separated by 1 min of rest were completed. Before and after each condition, subjects performed rapid, maximal isometric contractions of the elbow flexors with a dynamometer. Peak torque (maximal strength) and rate of torque development (explosiveness) were calculated from the torque-time curve data. Peak torque was considered the highest rolling 500 ms average, whereas RTD was determined from the slope of the torque-time curve from contraction onset to 50, 100, and 200 ms. A Wilcoxon test was used to examine changes within each condition. Results: Peak torque (p=0.63 – 0.612) nor any RTD outcomes (p=0.091- 0.866) changed following either condition. Conclusions: Our preliminary results suggest a potential small effect of fast MI on PT (+4%; p = 0.063), albeit not statistically significant, whereas RTD outcomes remained constant. As we recruit a larger sample size, a more powerful analysis will yield stronger evidence regarding the effects, if any, of different types of MI on acute muscle function.