Author(s): CALKINS, C., KRAEUTNER, S., JAKOBI, J., Institution: UNIVERSITY OF BRITISH COLUMBIA OKANAGAN , Country: CANADA, Abstract-ID: 1419

INTRODUCTION:
Mentally rehearsing a task with no overt movements is defined as motor imagery training (MIT), and its application can improve task performance. With increased age the ability to maintain steady force output (force steadiness) declines, and females are also less steady than males. The purpose of this study was to understand if a single session of MIT would improve force steadiness of isometric elbow flexion contractions of older and young females. It was hypothesized that MIT would improve force steadiness and increase corticospinal excitability during isometric elbow flexion contractions in older and young females. It was also hypothesized that older females would improve to a greater extent compared to young females.
METHODS:
Twenty-two young (aged 19-35) and thirteen older (aged 65-90) female participants were randomly assigned to a MIT group or control group. Both groups were tested in a block order. Blocks 1,3, and 5 involved participants performing isometric elbow flexion contractions at 10% of their maximal voluntary contraction. Blocks 2 and 4 involved participants performing MIT (training group) or viewing a documentary (control group). Motor evoked potentials (MEPs) were elicited within the last 5 seconds of each submaximal contraction in blocks 1,3 and 5.
RESULTS:
The MIT group were less steady than the control group in block one (p=0.02), and force steadiness improved in the older group with MIT in block three (p=0.008). There were no significant findings for MEPs (p>0.05). For visual (p=0.05) and global (p=0.04) motor imagery ratings from the MIT blocks, young had higher motor imagery ratings than older females. There was a significant negative relationship in older females between global (r=-0.715, p=0.035) and visual (r=-0.773, p=0.021) motor imagery ratings from block 2 and force steadiness in block 3, suggesting a higher global and visual motor imagery score was associated with increased ability to produce steady contraction in older females.
CONCLUSION:
This study demonstrated that motor imagery ability is maintained with aging and MIT can improve (or preserve) force steadiness in older females.