Fig 1.
Experimental setup of the 15-m sprint acceleration.
Fig 2.
Experimental setup of the squat jump.
Fig 3.
(A) Typical example of a force–velocity (F-V) profile obtained from squat jumps. Each closed circle plot represents raw mean force and velocity during a squat jump at a given load. The F-V relationship for this participant was F = F0 – αV, where F0 (theoretical maximum force) was 38.0 N/kg and α was 14.6 Ns/m. Pmax (24.8 W/kg), theoretical maximum power; V0 (2.60 m/s), theoretical maximum velocity. (B) Typical example of calculation of dynamic lower-limb strength (F1st, F5th, and F9th) corresponding to the mean leg extension velocities for the first, fifth, and ninth steps (V1st, V5th, and V9th) during sprint acceleration. The F1st (24.4 N/kg) for this participant was calculated by substituting the V1st (0.93 m/s) for the F-V relationship. Similarly, the F5th (19.7 N/kg) and F9th (18.8 N/kg) were obtained using the values of V5th (1.26 m/s) and V9th (1.31 m/s).
Table 1.
Descriptive data of sprint-related variables and parameters derived from the force–velocity profile.
Fig 4.
Correlations (95% confidence intervals) of the horizontal ground reaction force for the first, fifth, and ninth steps (left, center, and right columns, respectively) during 15-m sprint acceleration with parameters of the force–velocity profile and dynamic lower-limb strength.
F0, theoretical maximum force; Pmax, theoretical maximum power; V0, theoretical maximum velocity.
Fig 5.
Correlations (95% confidence intervals) of the resultant ground reaction force for the first, fifth, and ninth steps (left, center, and right columns, respectively) during 15-m sprint acceleration with parameters of the force–velocity profile and dynamic lower-limb strength.
F0, theoretical maximum force; Pmax, theoretical maximum power; V0, theoretical maximum velocity.