An exploration of the motor unit behaviour during the concentric and eccentric phases of a squat task performed at different speeds
Metadatos
Mostrar el registro completo del ítemAutor
Orantes González, Eva; Heredia Jiménez, José María; Lindley, Steven B.; Richards, Jim D.; Chapman, Graham J.Editorial
Taylor & Francis
Materia
Decomposition EMG Vastus lateralis Vastus medialis Motor unit behaviour Squatting
Fecha
2023-06-20Referencia bibliográfica
Eva Orantes-Gonzalez, Jose Heredia-Jimenez, Steven B Lindley, Jim D Richards & Graham J Chapman (2023): An exploration of the motor unit behaviour during the concentric and eccentric phases of a squat task performed at different speeds, Sports Biomechanics, [DOI: 10.1080/14763141.2023.2221682]
Resumen
Despite squatting being important in strength training and rehabilitation, few studies have investigated motor unit (MU) behaviour. This study explored the MU behaviour of vastus medialis (VM) and vastus lateralis (VL) during the concentric and eccentric phases of a squat exercise performed at two speeds. Twenty-two participants had surface dEMG sensors attached over VM and VL, and IMUs recorded thigh and shank angular velocities. Participants performed squats at 15 and 25 repetitions per minute in a randomised order, and EMG signals were decomposed into their MU action potential trains. A four factor (muscle x speed x contraction phase x sexes) mixed methods ANOVA revealed significant main effects for MU firing rates between speeds, between muscles and between sexes, but not contraction phases. Post hoc analysis showed significantly greater MU firing rates and amplitudes in VM. A significant interaction was seen between speed and the contraction phases. Further analysis revealed significantly greater firing rates during the concentric compared to the eccentric phases, and between speeds during the eccentric phase only. VM and VL respond differently during squatting depending on speed and contraction phase. These new insights in VM and VL MU behvaviour may be useful when designing training and rehabilitation protocols.