Of Sprinting Horizontal Velocity throughout the race is constantly changing Most Important part of the race Acceleration Maximum velocity Understanding Sprint Performance Horizontal velocity of an elite sprinter ID: 409859
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Slide1
Biomechanics
Of
SprintingSlide2
Horizontal Velocity throughout the race is constantly changing.
Most Important part of the raceAccelerationMaximum velocity
Understanding Sprint PerformanceSlide3
Horizontal velocity of an elite sprinter
Over 4 meters/sec at ground contact coming out of blocksIncreases to over 7 meters per second by end of the 2nd touch down
That is over half of the sprinters maximum velocity with in the first 3 steps of the start
Start Slide4Slide5
From powerful horizontal force to a more vertically directed force.
In part due to raising COGMechanics Transition Slide6
For the Start the goal is maximum horizontal force and minimizing force in all other directions
Transition phase into maximum velocityOnce maximum velocity is reached the goal is to maintain maximum velocity by producing maximum amounts of vertical force
Basic MechanicsSlide7Slide8
This means that Horizontal velocity is not the critical mechanical factor in sprint performance
Basic MechanicsSlide9
We can understand this change in focus by looking at Newton’s laws
Force= Mass(Change in velocity)/Ground time@StartHorizontal force=77.5*(7.0)/.60 = 905 N or 205lbs of horizontal force
Newton’s Laws
*77.5kg=170.8lbsSlide10
@ Maximum velocity
Horizontal force= 0@ StartVertical Force= 77.5*(1.0)/.150= 485N or 110lbs
Total Vertical Force=
750N+485N= 1235N or 277lbs
Newton’s LawsSlide11
As you transition into maximum velocity the horizontal force output decreases
This is not true of vertical forceBecause of gravity, sprinting is a series of alternating ground and air phases
Newton’s LawsSlide12
To account for this the change the vertical velocity in the upward direction must increase to about .5 m/s
This is also true in the downward direction so the total vertical velocity increase equals to 1.0 m/s
Newton’s LawsSlide13
Vertical force= 77.5*(1.0)/.087= 890N or 199 lbs
Total Vertical Force= 759N+890N= 1,640N or 367lbsNewton’s LawsSlide14
As horizontal velocity increases the segments increase as well.
When segments increase it has a negative impact on the runners ability to produce vertical forceAnother limiting factor is the body position
MechanicsSlide15
The body positioning of the sprinter at touchdown is actually producing horizontal braking forces
The touchdown point is actually located slightly in front of the COGThe best sprinters minimize this effect
MechanicsSlide16Slide17
Specific Performance Descriptors
Block DistancesCOG Distance at Set PositionSegment Angles at Set PositionSegment Angles During Block Clearance
COG Distance at Step 1 Touchdown
Segment Angles during Step 1COG Distance at Step 2 touchdown
Segment Angles during Step 2
Start MechanicsSlide18
Horizontal Velocity
Stride RateStride LengthGround Contact TimeAir Time
Time To Maximum Upper Leg Flexion
Critical Performance Descriptors at Maximum VelocitySlide19
The most successful sprinters focus on front side mechanics
Active recovery of the back side mechanics is importantDo not just “spin the wheels”
Front Side/ Back Side MechanicsSlide20
Hunter,J
., Marshall,R., McNair,P.(2005).
Relationships Between Ground Reaction Force Impulse and Kinematics of Sprint-Running Acceleration.
Retrieved from: Journal of Applied Biomechanics, 21,31-43
Kovacs,M
.
Speed Training: Linear Acceleration.
Retrived
from NSCA
Cavagna
, G.,
Komarek
, L.,
Mazzoleni
, S. (1971, May)
The Mechanics of Sprint Running.
Retrieved from: The Journal of Physiology, 217, 709-721
Mann, R. (2011).
The Mechanics of Sprinting an Hurdling.
References