Effect of Visual Feedback Information on Isometric Contraction of Forearm Flexor Muscles in Men and Women After Ischemic Stroke

Tomas Darbutas¹, Vilma Juodžbalienė¹, Albertas Skurvydas¹, Gražina Krutulytė², Inesa Rimdeikienė², Marius Brazaitis¹

¹Faculty of Sports Biomedicine, Lithuanian Sports University, ²Department of Rehabilitation, Medical Academy, Lithuanian University of Health Science, Lithuania

Key words: ischemic stroke; isometric contraction; accuracy; visual feedback.

Summary. The aim of this study was to determine the effect of visual feedback information (VFI) on the isometric contraction of the forearm flexor muscles in men and women after an ischemic stroke when doing a physical load at 20% of strength.

Material and Methods. The study included healthy subjects (n=20) and subjects after ischemic stroke (n=20). The study was conducted in Lithuanian Sports University. The measurements of maximum voluntary strength (MVS) and accurate isometric contraction were performed using an isokinetic dynamometer Biodex System Pro 3.

Results. The absolute errors of isometric contraction of the right arm muscles at 20% of MVS were similar in all the groups during the attempt with visual feedback information. The smallest absolute errors of the healthy subjects were 1.42±0.35 Nm when the task was performed with visual feedback and the greatest absolute errors were 4.69±0.95 Nm (P<0.01) while performing the task without visual feedback. Meanwhile, the smallest and greatest absolute errors of the subjects after ischemic stroke were 1.32±0.45 Nm and 5.05±0.63 Nm, respectively, while performing the task without visual feedback (P<0.01).

Conclusions. Maximum voluntary strength was greater in all the groups of men. The absolute errors of isometric contractions of the right and left arm muscles tended to increase in both the men and the women when there was no visual feedback information. The women and the men after an ischemic stroke produced greater absolute errors when performing the task with the right and left arm without visual feedback information than the healthy subjects.

Correspondence to T. Darbutas, Mosėdžio 7–36, 48177 Kaunas, Lithuania. E-mail: darbtoma@yahoo.com

Received 28 July 2012, accepted 30 December 2012