Exploring the Low Force-High Velocity Domain of the Force–Velocity Relationship in Acyclic Lower-Limb Extensions

Sports Medicine - Open

Table 1 Descriptive summary of the mechanical constraint and the force variables included in the computation, which was used to estimate the force developed over the lower limb push-off (Eq. 1) in the six resistive conditions

Condition	Description	Components included in force computation
Condition	Description	\(F_{{{\text{flywheel}}}}\)	\(F_{{{\text{chariot}}}}\)	\(F_{{{\text{friction}}}}\)	\(F_{{{\text{limbs}}}}\)	\(F_{{{\text{roll}}}}\)	\(F_{{{\text{spring}}}}\)
C_1RM	Acceleration of the chariot, the flywheel with friction, and the lower limbs	✓	✓	✓	✓	✓	×
C_50%Fmax	Acceleration of the chariot, the flywheel with friction, and the lower limbs	✓	✓	✓	✓	✓	×
C_ØFric-0S	Acceleration of the chariot, the flywheel (without friction), and the lower limbs	✓	✓	×	✓	✓	×
C_ØFric-2S	Spring assisted acceleration of the chariot, the flywheel (without friction), and the lower limbs	✓	✓	×	✓	✓	✓
C_Char-0S	Acceleration of the chariot and the lower limbs	×	✓	×	✓	×	×
C_Char-2S	Spring assisted acceleration of the chariot and the lower limbs	×	✓	×	✓	×	✓

The signs « ✓» and « ×» correspond to the inclusion or the exclusion of the force component into the computation of the force developed by the lower limbs over the entire push-off, respectively. C_1RM, Force developed at an extension velocity of ~ 0.3 m s⁻¹; C_50%Fmax, Force corresponding to 50% of isometric maximum; C_ØFric-0S, Force produced while accelerating the chariot, the flywheel (without friction), and the lower limbs; C_ØFric-2S, Force produced during spring-assisted acceleration of the chariot, the flywheel (without friction), and the lower limbs; C_Char-0S, Acceleration of the chariot without flywheel and the lower limbs; C_Char-2S, Spring assisted acceleration of the chariot (without flywheel) and the lower limbs; \(F_{{{\text{flywheel}}}}\), force to accelerate the flywheel; \(F_{{{\text{chariot}}}}\), force to accelerate the chariot;\(F_{{{\text{friction}}}}\), the force to overcome the frictional forces applied by the belt on the flywheel;\(F_{{{\text{limbs}}}}\), the force to accelerate the center of mass of the lower limbs; \(F_{{{\text{roll}}}}\), the internal resistive force of the flywheel; F_spring, the force of the tension springs