Ron Grigg Jacksonville University Maximum Velocity Defined Top End Speed Running Occurs after complete acceleration Requires highly coordinated movement and appropriate sequencing of muscle activation ID: 709981
Download Presentation The PPT/PDF document "Maximum Velocity- Technical Model" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Maximum Velocity- Technical Model
Ron
Grigg
Jacksonville UniversitySlide2
Maximum Velocity Defined
Top End Speed Running
Occurs after complete acceleration
Requires highly coordinated movement and appropriate sequencing of muscle activationSlide3
Speed = Stride Length x Stride Rate
Seems simple, BUT
Stride Length and Stride Rate are Inversely Proportionate
Must find optimal balance without artificial manipulationSlide4
2 Components of Stride Rate
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?Slide5
FORCE!!!!!!!
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?Slide6
POSTURE
When Posture is correct, movement of limbs is often correct.
When Posture is incorrect, movement of limbs CANNOT be correct! Slide7
POSTURE
Proper Posture = stability
Instability= dysfunctional movement= loss of elasticity
Limb movement originates in the CORESlide8
POSTURE
DYNAMIC STABILITY of Core
-strong muscles around spine
-slight posterior tilt of pelvis
-maintain ability for hips to move
*oscillation & undulation like a kayak paddleSlide9
POSTURE
HEAD, NECK, SPINE neutrally aligned
Allow for freedom of movement,
relaxation
, enhanced elastic energy return
Enhances FRONTSIDE mechanics, limits BACKSIDE mechanicsSlide10
Examining Sprint Stride
Stance Phase
Instant of Ground Contact to moment of toe-off
Flight Phase
Actions in air when not in contact with groundSlide11
Stance Phase-Ground Contact
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 contactSlide12
Stance Phase-Ground 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)Slide13
Stance Phase-Ground Contact
Body travels over and in front of support foot.
From absorbing forces, to applying vertical and horizontal forces.Slide14
Stance Phase-Ground Contact
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 beforeSlide15
Stance Phase-Toe Off
Posture!
Opposite hip forward and up
Thigh moving toward high knee position which places hamstring and
gluteal
muscles on stretchSlide16
Stance Phase-Toe Off
The best sprinters also Toe Off closer to Bottom Dead Center due to
increased vertical force production
.
Cue: “Push Up”Slide17
Flight Phase-Backside
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 groundSlide18
Flight Phase-Frontside
Opposite leg has reached high knee position
Thigh forcefully accelerates down and back towards the ground.
Lower leg will naturally “open up”Slide19
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.
Slide20
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
Slide21
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 Slide22
Continuous Loop
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-offSlide23
References
Dyson, Geoffrey- Mechanics of Athletics, 1977
Mann, Ralph- Mechanics of Sprinting and Hurdling, 2011
Young, Mike-
Maximum Velocity Sprint Mechanics