Are leg electromyogram profiles in squat is symetrical? (Case study)

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Are leg electromyogram profiles in squat is symetrical? (Case study)

Journal Title: Antropomotoryka. Journal of Kinesiology and Exercise Sciences - Year 2017, Vol 27, Issue 78

Abstract

The action of the central nervous system that controls neuromuscular functions reflect electromyograms (EMGs) profiles of muscle activity of the basic muscles. However, there seems to be a relationship between the EMGs profiles and the movement patterns (e.g., values of extremity joins angles). We want to find out how changes EMG profiles and movement patterns of the squat movement with increasing loads and especially we want to determine degree of symmetry of selected homologous muscles. Due to the lack of critical information addressing symmetry, we studied the EMG profiles of six homologous leg muscles (i.e. tibialis anterior, gastrocnemius, rectus femoris, biceps femoris, gluteus maximus and erector spinae) during squat movement depending on load size. For this purpose we checked the usefulness of the multimodular measuring system (SMART-E, BTS) and force plate Kistler. Smart Analyser software was used to create a database allowing the chosen EMG profiles and movement patterns to be compared. In this study participated eleven healthy man, however two were selected for analysis. The first of subject was 36 years (body mass 82 kg; body height 180 cm; 1RM in full squat 140 kg). The second one was 28 years (body mass 90 kg; body height 183 cm; 1RM in full squat 110 kg). The subjects performed consecutive sets of a single repetition of full squat with the increasing load (70, 80, 90 and 100% 1RM the anticipated maximum weight), until the appointment of one repetition maximum. For analysis, however, only samples with moderate and maximal loads (70% and 100% 1RM, respectively) were selected. The sum of the differences in normalized amplitude values of individual pairs of homologous muscles was taken as a measure of symmetry/asymmetry of the EMG profile. The load increase of the squat contributed to the increase asymmetry of the profiles of pairs homologous muscles of the lower extremities. Greater asymmetry of subject A.M. in a squat with a load of 100% 1RM resulted that the fluidity of the movement was worsened.<br/><br/>

Authors and Affiliations

Krzysztof Kmiecik, Henryk Król, Grzegorz Sobota

Keywords

squat EMG muscle symmetry

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EP ID EP273784
DOI -
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