Concurrent EMG feedback acutely improves strength and muscle activation
2012 (English)In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 112, no 5, 1899-1905 p.Article in journal (Refereed) Published
The purpose of this study was to investigate the acute effects of electromyographic (EMG) feedback on muscle activation and strength during maximal voluntary concentric and eccentric muscle actions. 15 females performed two sets of three lengthening and three shortening maximal voluntary isokinetic knee extensions at 20A degrees A s(-1) over 60A degrees range of motion. After the first set, subjects were randomized to either a control group (n = 8) or a feedback group (n = 7). In the second set, the control group performed tasks identical to those in the first set, whereas the feedback group additionally received concurrent visual feedback of the EMGrms from Vastus Medialis (VM). Knee extensor strength and EMG activation of VM, Vastus lateralis (VL) and hamstrings (HAM) were measured during the MVCs. Analyses were performed separately in a 1 s preactivation phase, a 1 s initial movement phase and a 1 s late movement phase. EMG feedback was associated with significantly higher knee extensor strength in all phases (20.5% p < 0.05, 18.2% p < 0.001 and 19% p < 0.001, respectively) for the eccentric MVCs and in the preactivation phase (16.3%, p < 0.001) and initial movement phases (7.2%, p < 0.05) for concentric MVCs. EMG feedback from VM further improved activation in VM and HAM but not VL. These findings suggested that concurrent visual EMG feedback from VM could acutely enhance muscle strength and activation. Before recommending implementation of EMG feedback in resistance training paradigms, the feedback parameters needs to be optimized and its long-term effects needs to be scrutinized.
Place, publisher, year, edition, pages
2012. Vol. 112, no 5, 1899-1905 p.
Myofeedback, Eccentric, Concentric, Strength training, Activation, Biofeedback
IdentifiersURN: urn:nbn:se:kth:diva-95085DOI: 10.1007/s00421-011-2162-2ISI: 000302745700033ScopusID: 2-s2.0-84861527258OAI: oai:DiVA.org:kth-95085DiVA: diva2:527436
QC 201205212012-05-212012-05-142012-05-21Bibliographically approved