The Immediate Effects of Electromyographic Biofeedback on Corticomotor Excitability of the Quadriceps in Healthy Individuals

Objective: The objective of this study was to determine the immediate effects of a single bout of electromyographic biofeedback on corticomotor excitability in healthy individuals. Design: A cross- over study with a one-week period between each testing session was conducted in a laboratory setting. Participants: Twelve participants (6 male, 6 female; 21.41 ± 4.41 years; 172.82 ± 11.23 cm; 72.58 ± 15.77 kg). Procedure: Participants were position in the Biodex System 2 dynamometer to measure maximal voluntary force to establish a baseline MVIC value for each testing session. Submaximal contractions at five percent of this maximal contraction were used to standardize voluntary contraction during corticomotor testing. A Magstim Rapid was used to administer transcranial magnetic stimulation to the motor cortex to measure corticomotor excitability. Active motor threshold (AMT) was established as the lowest intensityrequired to elicit a motor evoked potential (MEP) of =100µV amplitude in at least 5 of 10 trials. Five MEPs were collected at AMT. The participants then performed a MVIC of the quadriceps. When maximal effort plateaued a stimulus was given and the MEP peak-to-peak amplitude was recorded for analysis. This was performed for 5 consecutive trials with 60 seconds of rest between each MVIC. During the electromyographic biofeedback (EMG-BF) testing session a Myotrac Infinity handheld biofeedback unit was used to monitor electrical activity of the vastuslateralis. A target line was established on the biofeedback unit at 110% of their peak EMG values. Participants performed a MVIC while using EMG-BF. When maximal effort plateaued, magnetic stimulus was produced over the motor cortex and the quadriceps MEP peak-to-peak amplitude was recorded for analysis. This was performed for 5 consecutive trials with 60 seconds of rest between each MVIC. Maximum muscle response (Mmax) was recorded and used to normalize MEP. Statistics: Significance determined using dependent t-tests between thechanges in MEP amplitude during the control and EMG-BF sessions (p< 0.05). Cohen’s d effect sizes with corresponding 95% confidence intervals were calculated. Results: The percent change scores for MEP amplitude at AMT were significantly greater in the biofeedback condition compared to the control (t 11 = -2.308, p= .041). Large effect sizes were found for both the control (d= 3.92, 95% CI = 2.45-5.12), and biofeedback condition, (d= 2.77, 95% CI =1.58- 3.78). A moderate effect size was found between the two conditions, (d= 0.62, 95% CI= -0.22- 1.42). Conclusion: The results from this study suggest that a single bout of EMG-BF can be used to increase corticomotor excitability in healthy individuals.

Name thesis:degree_name

Master of Science in Exercise Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Exercise Science

Grantor dc:publisher

University of Toledo

Year dc:date

2013

Author dc:creator

• Florea , David, II

Contributors dc:contributor

• Pietrosimone, Brian

• Kinesiology

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=toledo1364471334

OAI identifier oai:identifier

oai:etd.ohiolink.edu:toledo1364471334