Effects of Foot Position during Squatting on the Quadriceps Femoris: An Electromyographic Study.
Weightlifters have commonly believed that changing joint position can alter specific muscle activation. The magnitude of force produced by a muscle is highly dependent upon the length of the muscle. The purpose of this study was to determine the effect of foot positioning on muscle activation of the superficial quadriceps as measured by surface electromyography (sEMG) during a functional squatting movement in healthy adults. Twenty physically active asymptomatic adults (7 females and 13 males) were included in the study while four different foot positions (Neutral, Internally Rotated, Externally Rotated, and Staggered) were assessed. Three quadriceps muscles (Rectus Femoris (RF), Vastus Medialis Oblique (VMO), and Vastus Lateralis Oblique(VLO) were measured. Raw EMG was transformed using a root mean square algorithm. Six one-way repeated measure ANOVAs were conducted to examine the peak and average RMS amplitude for each muscle across each condition, with an alpha level of 0.05 set a priori. Across all foot positions only the Staggered foot position reached statistical significance when compared to all other foot positions for each muscle group. Results suggest that altering the foot position during a partial weight squat has little to no effect on the EMG amplitudes of the quadriceps. However, more research is needed to examine the concentric and eccentric phases of the squatting motion separately with the addition of full weight bearing squats.
Interdisciplinary Health Sciences, The University of Texas at El Paso, El Paso, TX, USA.
Nicholas
N
Murray
Schmid College of Science and Technology Physical Therapy, Crean School of Health and Life Sciences, Chapman University, Orange, CA, USA.
Daniel
D
Cipriani
School of Exercise and Nutritional Sciences, San Diego State University, San Diego, CA, USA.
Denise
D
O'Rand
Department of Kinesiology and Physical Therapy Program, The University of Texas at El Paso, El Paso, TX, USA.
Rebecca
R
Reed-Jones
Length tension; Q-angle; lower extremity biomechanics; quadriceps angle