Concentric and eccentric inertia–velocity and inertia–power relationships in the flywheel squat

Load Quantification and Testing Using Flywheel Devices in Sports

“…Previous research has reported that a near-maximal concentric contraction is a necessary condition to obtain a demanding eccentric contraction (Beato and Dello Iacono, 2020). Therefore, considering the maximum nature of each concentric contraction together with the need to know the magnitude of the load during the eccentric contraction (i.e., eccentric:concentric ratio [E:C ratio]), practitioners should consider to quantify both outputs during any given exercise (Carroll et al, 2019;McErlain-Naylor and Beato, 2020). The flywheel exercise intensity depends on the inertial discs used (i.e., modifying the moment of inertia) and mechanical characteristics of the device (e.g., cylinder type).…”

“…Moreover, recent research has shown that both exercise intensity and E:C ratio also depend on the axis type (i.e., horizontal regular cylinder or vertical conical cylinder) and radius of the flywheel device used (Núñez et al, 2020), showing higher mechanical outputs and larger eccentricoverload when horizontal cylinders were used compared to their vertical conical counterparts (Muñoz-López et al, 2021). In addition to inertial discs selected and the characteristics of the flywheel device used, the movement velocity, which is primary depended of the participants' strength and physical characteristics, are key determinant of both concentric and eccentric outputs (e.g., power) of a flywheel exercise (Maroto-Izquierdo et al, 2019;McErlain-Naylor and Beato, 2020).…”

“…Recently, the use of inertia-power and inertia-velocity relationships have been investigated (Carroll et al, 2019;McErlain-Naylor and Beato, 2020). It has been reported that when performing any given flywheel exercise both concentric and eccentric velocity decrease while inertial load increases (McErlain-Naylor and Beato, 2020).…”

“…Recently, the use of inertia-power and inertia-velocity relationships have been investigated (Carroll et al, 2019;McErlain-Naylor and Beato, 2020). It has been reported that when performing any given flywheel exercise both concentric and eccentric velocity decrease while inertial load increases (McErlain-Naylor and Beato, 2020). But this is not the case for mechanical power, which highlights that, although peak power is often used as the main parameter to quantify flywheel exercise intensity (e.g., during a squat), power output should not be used as unique parameter to evaluate exercise intensity (McErlain-Naylor and Beato, 2020;Worcester et al, 2020).…”

“…Although the concentric contraction in flywheel exercises have received lower interest compared to the eccentric contraction, it plays a key role in the obtainment of specific adaptations (both neural and morphological), and it is a necessary component for the development of the subsequent eccentric contraction (Norrbrand et al, 2008;Maroto-Izquierdo et al, 2017;Beato et al, 2019;Beato and Dello Iacono, 2020). For that reason, it is important to quantify kinetic and kinematic variables, such as velocity, power, or force, during both concentric and eccentric actions of the flywheel exercise to individually monitor and adjust training volume and intensity to fit the needs of each participant (Suchomel et al, 2019a;McErlain-Naylor and Beato, 2020;Piqueras-Sanchiz et al, 2020). Although the evidence to effectively prescribe flywheel training volume and intensity to achieve specific goals is still limited (Beato and Dello Iacono, 2020), load quantification provides an objective method to determine the precise number of repetitions per set or per session and the right inertia load needed to achieve the aims of training.…”