Sprinting

Question 1

What are the four sprinting phases?

Answer 1

1. Starting Block Phase
2. Acceleration Phase
   - 75% of total acceleration achieved in first 7 steps
3. Constant Speed Phase
4. Deceleration Phase

Question 2

For the deterministic model of running speed what do the following stand for?
DCM
TO
TD
COM

Answer 2

DCM = Distance to Centre of Mass

TO = Take Off

TD = Touch Down

COM = Centre Of Mass

Question 3

What are five variables that can be measured by motion analysis techniques (Kinematics)?

Answer 3

1. Horizontal/Vertical Velocity
2. Step Length
3. Distances
4. Posture (angles)
5. Temporal variables (e.g. contact time)

Question 4

What are the three variables that can be measured by external force measurement (Force platform) measurements (Kinetics)?

Answer 4

1. Ground Reaction Forces (GRF)
2. Impulse
3. CM vertical/horizontal velocity

Question 5

What are the two known constant variables affecting sprinting?

Answer 5

1. Gravity

2. Air resistance

Question 6

What anthropometric variables should be considered?

Answer 6

Physique (height, limb lengths)

Question 7

What % is the contact phase?

Answer 7

40-45% of stride time

Question 8

What % is the flight phase?

Answer 8

55-60% of stride time = PROJECTILE MOTION!

Question 9

What is Stride length (SL)?

Answer 9

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)

Question 10

What is Step length?

Answer 10

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

Question 11

What is Takeoff Distance (DCM TO)?

Answer 11

The horizontal distance from the CoM to a point perpendicular to the toe of the take-off foot (~26% of SL).

Question 12

What is Flight Distance (FD)?

Answer 12

The horizontal distance the COM covers while in the air (~57% of SL).

Question 13

What is Touchdown Distance (TD)?

Answer 13

The horizontal distance from the COM to a point perpendicular to the toe of the leading leg (~17%)

Question 14

What does impulse determine?

Answer 14

Impulse determines final (take-off) velocity

Question 15

What three things happen as running velocity increase?

Answer 15

1. SL and SR increase
2. Contact time reduces
3. Ratio changes in favour of step rate

Question 16

What phases occur during contact phase?

Answer 16

Braking phase

Propulsion phase

Question 17

What phases occur during flight phase?

Answer 17

Upward phase

Downward phase

Question 18

What are some key muscles involved in sprinting?

Answer 18

ILIOPSOAS

GLUTEUS MAXIMUS

GLUTEUS MEDIUS

VASTUS MEDIALIS

RECTUS FEMORIS

HAMSTRINGS

TIBIALIS ANTERIOR

GASTROCNEMIUS

SOLEUS

Question 19

How do RESISTED training methods influence sprint kinematics?

Answer 19

Improve the drive phase

Question 20

How do ASSISTED training methods influence sprint kinematics?

Answer 20

Improve the max velocity stage

Question 21

What four neuromuscular factors affect production of impulse during sprinting?

Answer 21

1. Fibre distribution
2. Neural drive (strength gains not muscle growth)
3. Muscular co-ordination
4. Motor nerve conduction velocity