Research on the Relationship between Impulse Characteristic and Velocity during Support Period in Different Pushing Phase

Objective: To explore the relationship between impulse characteristics and velocity of the skeleton athletes during support period in different pushing phase. Methods: The Vicon three-dimensional motion capture system and Kistler force plate were used to simultaneously collect the kinematics(velocity, braking time, impulsive time) and dynamics parameters(ground reaction force,impulse) of 17 national skeleton athletes during pushing phase. Results: 1) Compared with step 3, the braking time at 20 m was longer and the propulsive time was shorter, the peak braking force and vertical force were greater but the peak propulsive force was smaller, the horizontal braking impulse was larger but the horizontal propulsive and net horizontal was smaller; 2) At step 3 and 20 m,the horizontal propulsive impulse, net horizontal impulse and velocity were strongly correlated(r=0.650, r=0.624, r=0.615, r=0.850, P<0.01); the vertical impulse and the velocity of step 3 was correlated positively(r=0.662, P<0.01), and the horizontal braking impulse was positively correlated with the velocity at 20 m(r=0.536, P<0.05). Conclusions: For the high-level skeleton athletes, a large propulsive and net horizontal impulse are extremely important for push velocity, and it may be more beneficial to generate a relatively large vertical impulse during the acceleration push phase; meanwhile, the role of the braking impulse during the maximum speed phase should not be neglected.