SPRINT MECHANICS: WHAT TO LOOK FOR & HOW TO

EFFECTIVELY MAKE CHANGES!

Mike Young, PhD HPC - Athletic Lab

Cary, NC

@mikeyoung #speedsummit

•General Concepts of Sprinting

•Motor Learning Fundamentals

•Optimizing Acceleration Mechanics

•Optimizing Transition Mechanics

•Optimizing MaxV Speed Mechanics

•Take Home Points

GENERAL CONCEPTS OF

SPRINTING

by Hugo Faasta

BACK SIDE MECHANICS

Refers to the motions of the swing leg that occurs BEHIND the body

FRONT SIDE MECHANICS

Refers to the motions of the swing leg that occurs IN FRONT of the body

ACCELERATION CHARACTERISTICS• Velocity @10m: ~8.2 m/s!

• Ground Contact Time: ~0.17 sec!

• Height of foot @ 1st step: 12-30cm!

• Stride Frequency: 3.6-4 Hz!

• Stride Lengths: ~1.5m first step

*Maximal Velocity: ~12.8 m/s!

!

!

*Ground Contact Time: ~0.08 sec!

*40-45 steps for sub 9.80 100m

*Stride Frequency: ~5 Hz!

!

!

*Stride Velocity: ~300 deg / sec!

*Stride Lengths: 2.25-2.7m

MAXIMAL VELOCITY CHARACTERISTICS

KINETIC PARAMETERS• Ground reaction forces

approaching 5x bodyweight!

• Muscle forces in excess of 7x bodyweight

Sprinting 101

Small Mass +

Big Force +

Right Direction +

Minimal Time

Run Faster

• To increase running speed an athlete must increase force to the ground in the appropriate direction and do so over increasingly shorter periods of time!

• Minimize horizontal braking forces*!

• Increase propulsive forces

FORCE DEVELOPMENT & SPRINTING

Horizontal vs Vertical Propulsive Forces....!and why you don’t have to pick a side

VERTICAL FORCE MATTERS…

Rela%onships,among,jumping,performances,and,sprint,parameters,during,maximum,speed,phase,in,sprinters,,by,Kale,,Asci,,Bayrak,and,Acikada,,in,Journal,of,Strength,and,Condi%oning,Research,,2009!

from Strength & Conditioning Research

…BUT SO DOES HORIZONTAL FORCE

THE LEG AS A SWINGING SPRING

• Refers of the ability of the leg to act as like a spring

• Momentum is developed during acceleration

• Body will move at same rate unless acted on by unbalanced forces

• Two external forces will cause deceleration

• Leg stiffness increases vertical impulse, shortens ground contact and increases elastic return

INCREASE LEG STIFFNESS

• Increased vertical force produces:!

• Greater displacement!

• Stiffer spring!

• Better maintenance of momentum

VERTICAL FORCE PRODUCTION

Vertical Displacement?

The path of COM will follow a sinusoidal curve when viewed in the sagittal plane

COM reaches apex in flight

COM low point during support

Vertical force production is the key component of top-end

speed and that in turn influences the ability to

maintain a slight increase in stride length and stride

frequency

Dan Pfaff

Charlie Francis

To go faster, you need more force. The more force you apply, the

higher you will rise off the ground.

Better sprinters may appear to bounce

In reality, flight times are similar and ground contact times are shorter

• Stride frequency is comprised of two components: !

1. Ground contact time !

2. Flight time!

• The best sprinters spend less time on the ground !

◦ Greater frequency

MORE SPRINT MATH

The benefit of greater force application is two-fold:!• Increased stride length • Increased stride frequency

STRIDE LENGTH &

FREQUENCY

To run faster there is only ONE solution

Apply More Mass Specific Force to

the Ground!

Motor Learning

Sprinting is an extremely complex motor task involving repeated rapid ‘switching on and off’

of practically every muscle in the body

Dr. Ralph Mann

Sprinting fast is an unnatural activity

������������������

Loren Seagrave

TRUE learning is assessed by retention

Things to Consider

Intrinsicvs.

Augmented feedback

Knowledge of resultsvs.

Knowledge of performance

Novicevs.

Expert

X

Internal vs External Cues

Feedback

Frequency

Clear. Concise. Concrete.

Accelerate like a plane taking off

Elbow the short person

Hit the ground like a sledge hammer

You’re running like a hamster in a spinning wheel

Make your legs like pistons

Good Feedback is like Triage… Don’t fix a hangnail before a heart attack

Optimizing

Mechanics

General Sprinting Mechanics

•Better sprinters are front-side

dominant•Better sprinters have shorter

contact times

•Full extension neither needed

nor beneficial

•Ideal touchdown characterized

by swing knee even with

support knee

POS TU URE

The first most important

aspect of speed is posture.

Tom Tellez

Posture is like the mast and rudder for the limbs

Posture

Trunk Erect

Head Level

Hips Tall

Posture

• Movements of the limbs originate from the core of the body!

• Proper stabilization and alignment of the core ensures appropriate movements of the limbs

POSTURE

PELVIC TILT

Posterior Tilt = less hamstring tension, more QFM tension!

Anterior Tilt = more hamstring tension, less QFM tension

Acceleration: What to See. What to Say.

What to See

• Big split of arms & legs

• Forward lean (from the ankles)

• Neutral postural alignment pushing through long axis of body

• ‘Complete’ pushes & triple extension

• Low heel recovery

• Gradual progression of body angles

What to Say

• “Knees to chest”

• “Shade the sun”

• “Feel the feet behind you”

• “Push the ground away”

• “Legs like pistons”

• “Push, Push, PUSH!”

• “Drag the toe” (even though you don’t want them to)

• “Step over the ankle”

• “Push yourself up”

Transition: What To See. What to Say.

What to See

• Continued progression of body angles

• Preservation of posture

• Gradual changes in limb movement magnitude

• Progressively higher heel recovery during swing phase

What to Say

• “Push yourself tall”

• “Tuck the hips”

• “Cheek to cheek”

• “Step over the ankle, step over the calf, step over the heel”

Top Speed: What To See. What To Say.

EFFECTIVE GROUND CONTACT POSITION

What to See

• Upright posture

• Powerful & dynamic arm swing (not locked at 90 deg)

• High knee recovery

• Front side dominance

• Relaxation in face, shoulders, hands

• Foot contact under the hips

• ~Vertical shin angle at GCT

• Pre-activation prior to contact

What to Say

• “Balance a bowl on your head”

• “Slam the elbows down”

• “Step over the knee”

• “Feel everything in front”

• “Imaging you have a rubber band from you heel to your butt”

• “Make your eyelids jiggle”

• “Run tall and bounce”

• “Push up” ….or “Push down”

• “Be a super bouncy ball”

Creating a learning environment

Creating a learning environment

Try to coach without “coaching” by

creating an environment that

facilitates motor learning

Create contextual

interference by varying

trial type & order

Tools & specific environments can make motor patterns idiot proof

Block Serial Random

Falling Start! Falling Start! Crouch StartFalling Start! Crouch Start Falling Start!Falling Start! Starting Blocks Crouch StartFalling Start! Falling Start! Starting Blocks

Crouch Start Crouch Start Falling Start!Crouch Start Starting Blocks Starting BlocksCrouch Start Falling Start! Crouch StartCrouch Start Crouch Start Falling Start!

Starting Blocks Starting Blocks Starting BlocksStarting Blocks Falling Start! Crouch StartStarting Blocks Crouch Start Starting BlocksStarting Blocks Starting Blocks Falling Start!

Increase Contextual Interference to Enhance Skill Acquisition

Practice Variability? Increasing Variability Enhances Learning

Surface

Weather

Block position

Gun vs Clap

Alone or with partner

FRAMEWORK FOR SKILL ACQUISITION

Contextual Interference

Movement & Task Variability

Low Practice Variability

Beginners

Experts

Intermediate

High Practice Variability

Low

Contextual Interference

High

Contextual Interference Wu, 2008

Use Tools And environments that facilitate learning

SPRINTING IS A SKILL

SPRINTING FASTER IS THE RESULT OF PUTTING MORE FORCE IN TO THE GROUND AT AS LITTLE BODY MASS AS POSSIBLE

BETTER PRACTICE DESIGN IMPROVES SKILL ACQUISITION WHICH ALLOWS MOVEMENT TO BE AUTOMATIC, REFLEXIVE & EFFICIENT

THE WAY A MESSAGE IS DELIVERED IS JUST AS IMPORTANT AS THE MESSAGE

UNDERSTAND THE BASICS OF MOTOR LEARNING BEST PRACTICES

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THANKS