Influence of exercise instruction method on the activation of vastus medialis obliques and vastus lateralis during a mini-squat

The aim of this study was to investigate the effect of different exercise instruction methods on the activation of vastus medialis oblique (VMO) and vastus lateralis (VL) while performing a mini-squat. Thirty healthy volunteers were recruited from the student population of the University of Limerick and were randomised to one of three instruction groups; either (a) verbal instruction, (b) visual demonstration or (c) a combination of both instruction methods. Surface electromyographic activity was collected during the mini-squat for each instruction group and this was expressed as a percentage of maximal voluntary isometric contraction (MVIC). One-way ANOVAs were used to detect differences between groups. There were no significant differences noted in the muscle activation of VMO and VL, or the ratio of VMO: VL activity, when performing the mini-squat under the thee different types of instruction. This finding suggests that the type of instruction method had little influence over the performance of this relatively simple motor task amongst a healthy young population. This contrasts with previous studies of more complex motor tasks. Potential reasons for the discrepancies, and implications for future studies, are discussed.