Ron Grigg
Jacksonville
University

Top End Speed Running
Occurs after complete acceleration
Requires highly coordinated movement and appropriate sequencing of muscle activation

Speed = Stride Length x Stride Rate
Seems simple, BUT
Stride Length and Stride Rate are
Inversely Proportionate
Must find optimal balance without artificial manipulation

Air Time- there is almost no difference in air time results of sprinters of ALL abilities
Ground Time – the BEST sprinters spend less time on the ground.
BUT HOW?

Greater force applied at ground contact improves BOTH stride length and stride rate.
Greater force = greater displacement= greater SL
Greater force= repelled from the ground faster= greater SR
Therefore “BIG FORCE, SHORT TIME”
BUT HOW?

When Posture is correct, movement of limbs is often correct.
When Posture is incorrect, movement of limbs CANNOT be correct!

Proper Posture = stability
Instability= dysfunctional movement= loss of elasticity
Limb movement originates in the
CORE

DYNAMIC STABILITY of Core
-strong muscles around spine
-slight posterior tilt of pelvis
-maintain ability for hips to move
*oscillation & undulation like a kayak paddle

HEAD, NECK, SPINE neutrally aligned
Allow for freedom of movement,
relaxation, enhanced elastic energy return
Enhances FRONTSIDE mechanics, limits BACKSIDE mechanics

Stance Phase
Instant of Ground Contact to moment of toe-off
Flight Phase
Actions in air when not in contact with ground

Foot as close to Bottom Dead Center as possible to minimize breaking forces
Tibia (shin) perpendicular to track
Thighs in line with each other knee to knee at contact

Must absorb impact forces in initial stance phase
Failure (collapsing) due to poor posture or lack of leg stiffness
Failure to properly prepare during flight phase (will be discussed)

Body travels over and in front of support foot.
From absorbing forces, to applying vertical and horizontal forces.

Active forward upward movement of swing leg thigh will increase forces applied to ground on stance leg
Swing foot steps over opposite knee with heel tight to buttocks while thigh is moving forward, NOT before

Posture!
Opposite hip forward and up
Thigh moving toward high knee position which places hamstring and gluteal muscles on stretch

The best sprinters also Toe Off closer to Bottom Dead Center due to increased vertical force production.
Cue: “Push Up”

Minimize Backside Mechanics
Knee flexion after toe off (heel to butt) is a result of aggressive hip flexion
(high knee) once athlete has left the ground

Opposite leg has reached high knee position
Thigh forcefully accelerates down and back towards the ground.
Lower leg will naturally “open up”

Flight Phase-Ground Preparation
Must prepare for Stance while in Flight
Elite Ground Contact Times of less than .10 require prior preparation in order to exhibit appropriate force in such short time.

Flight Phase-Ground Preparation
ANKLE- weakest link in leg spring system
Neutral or slight dorsiflexion position
• allows contact to be close to BDC
• puts gastroc-soleus on stretch for better elastic force production

Arm Swing
To counterbalance the rotary momentum of the legs
Contribute 7% to VERTICAL forces
Originates from the shoulders
MUST open and close at the elbow

Position of limbs during swing phase influences capacity to produce force through increased stretch of muscles
Position of limbs in flight directly influence their positioning at ground contact
Position of limbs at ground contact affect magnitude and direction of force application
Force applied during ground contact influences swing kinematics immediately following toe-off

Dyson, Geoffrey- Mechanics of Athletics,
1977
Mann, Ralph- Mechanics of Sprinting and
Hurdling, 2011
Young, Mike- Maximum Velocity Sprint
Mechanics