Sprinting Flashcards
What are the four sprinting phases?
- Starting Block Phase
- Acceleration Phase
- 75% of total acceleration achieved in first 7 steps - Constant Speed Phase
- Deceleration Phase
For the deterministic model of running speed what do the following stand for? DCM TO TD COM
DCM = Distance to Centre of Mass
TO = Take Off
TD = Touch Down
COM = Centre Of Mass
What are five variables that can be measured by motion analysis techniques (Kinematics)?
- Horizontal/Vertical Velocity
- Step Length
- Distances
- Posture (angles)
- Temporal variables (e.g. contact time)
What are the three variables that can be measured by external force measurement (Force platform) measurements (Kinetics)?
- Ground Reaction Forces (GRF)
- Impulse
- CM vertical/horizontal velocity
What are the two known constant variables affecting sprinting?
- Gravity
2. Air resistance
What anthropometric variables should be considered?
Physique (height, limb lengths)
What % is the contact phase?
40-45% of stride time
What % is the flight phase?
55-60% of stride time = PROJECTILE MOTION!
What is Stride length (SL)?
The horizontal displacement of the body during one
stride
(The beginning of a phase by one limb until the beginning of the same phase by the SAME limb)
What is Step length?
The horizontal displacement of the body during one step
the beginning of a phase by one limb until the beginning of the same phase by the Other limb
What is Takeoff Distance (DCM TO)?
The horizontal distance from the CoM to a point perpendicular to the toe of the take-off foot (~26% of SL).
What is Flight Distance (FD)?
The horizontal distance the COM covers while in the air (~57% of SL).
What is Touchdown Distance (TD)?
The horizontal distance from the COM to a point perpendicular to the toe of the leading leg (~17%)
What does impulse determine?
Impulse determines final (take-off) velocity
What three things happen as running velocity increase?
- SL and SR increase
- Contact time reduces
- Ratio changes in favour of step rate
