The Block Start and Accerlartion

Loren Seagrave

Director of Track & Field and Cross Country

Director of Speed and Movement

Phases of Acceleration (Linear)

• The Start

•Greatest Rate of Acceleration

• Pure Acceleration

•Slope of Acceleration Still Steep

• Transition

•Neuro-Mechanical Link to Vmax

Global Considerations of the Start and Acceleration Phases

Force = Mass X Acceleration

Force/Mass = Acceleration

Limb Length Matters

Global Considerations-Start & Acceleration Sprinters Don’t Have Jet Propulsion

Inverse Relationship between Velocity

and Ground Time

Direct Relationship between Velocity

and Air Time (with Limits)

Contractile Power and Elastic Power

Characteristics for Evaluation

– Big Force

– Short Time

– Proper Direction

– Optimal Range of Motion

The Start

“The Start is reaction time, force application and the first two steps”, Speed Dynamics Sprint Training Volume 1 (circa 1989) – spoken by Kevin O’Donnell

Winning Drills for Women – Bertucci and Crawford

Don’t Kick the Ball Drill

Stride Frequency is high at the beginning then increases, Speed Dynamics Sprint Volume 1

First Three Phases in the Sprint Race

15 meters 5 m

IN OUT

20m 15m 20m

PUSH-PUSH-PUSH

Hip Extension-

Acceleration

PURE ACCELERATION TRANSITION

15 meters 5 m

IN OUT

20m 35m 40m

DRIVE TALLER

Hip Extension-Max

Velocity

Sprint

Sta

rt

Neuro-Biomechanics of Pure Acceleration

Residual Phase

Recovery Phase

Transition Phase

Ground Preparation Phase

Front Side Ground Phase

Backside Ground Phase

The Athlete’s Mission Statement

Reduce the Amount of Time Needed to Apply the Required

Force into the Ground by 0.005 Seconds.

Reduce the Amount of Time Needed to

Recovery the Limb Through the Required Range of Motion by 0.005 Seconds.

First Consideration for Block Placement

Which Foot is on the Front Block?

Evaluation of the Start Action of World Class Female Sprinters Proceedings of the First IOC World Congress on Sport Sciences Colorado Springs 28 October-3 November 1989, 157. VAN COPPENOLLE H, DELECLUSE C, GORIS M, DIELS R, SEAGRAVE L, KRAAYENHOF H

First Consideration for Block Placement

Which Foot is on the Front Block?

– How is this best determined?

• Fold your arms on your chest. (Johnson,B)

• Hop-Hop Start (Even Stance)

Second Consideration for Block Placement

What is the Distance of the Front Pedal from Starting Line?

– Conventional

• Two Foot Lengths

– Maximum Distance

(Santos, J)

• Knee on Line

• Foot Plantar Flexed

Third Consideration for Block Placement

What is the Distance of the Rear Pedal from the Front Pedal?

– Front Pedal so Projection Angle is 90 Degrees to Surface of the

Pedal

– Rear Pedal Between 30 or 35 Degrees and 45 Degrees (when

lowest setting)

Preparation for Loading into the Starting Blocks

Disappear inside a Phone Booth (Wells, T)

The Argument for Dual Personalities in Sprint Start (Reardon, J)

Increase of “Neural Drive”

Ritual to Turn Light Bulb into Laser Beam - Coherent Entrainment

(Kwai Chang Caine)

The “On Your Marks” Position

Hand Position

– Hand Spacing and Alignment

– Hand Configuration

– Shoulder Position

The “On Your Marks” Position

Foot Position

– May Vary With Block Pedal Height

– Medium Spacing, Equi-Distance

– Vertical Alignment of Feet & Thighs

The “Set” Position

Front Knee Angle Approx 90 Degrees

Rear Knee Angle between 120 & 140 Degrees

Hips Higher than Shoulders

Center of Mass Anterior to the Front Pedal

Shoulders Above the Hands

Block Acceleration

Synchronous Double Leg Force

Summation of Hip and Back Extension Forces

Length of 1st Step

Length = Cos 45 X Xiphoid Height (Wells, T)

Factors Determining 1st Step Length

– Leg Length

– Muzzle Velocity

– Angle of Take Off

– Air Time

Mechanics of 1st Step

Utilize Block Reaction Forces with Active Hip Flexor Action (Thigh

Pops Forward)

Foot Stays Low (Almost Drags)

Ankle Dorsi-Flexed (Sole Down)

Shin Angle More Vertical (ATM)

Active Landing (NFS)

Anticipatory Firing (Firm Foot)

High Angular Acceleration @ Hip

Mechanics of 2nd Step

Maintain Step Length Over First Step

Almost Identical Recovery Action

Identical Air Time

Acceleration Pattern

There is a regular acceleration pattern that gives optimal results

(Winckler, G)

The Rate of Incremental Increase is Athlete Dependent.

Empirically the Highest Level Athletes Can Increase by 15% of

Trochanteric Leg Length.

Pure Acceleration Phase

Duration is about 2.0 Seconds

For Top Level Sprinters about 15 meters (Tabachnik, B)

Force is Generated Primarily by Muscle Contraction.

Transition Phase

Serves as the Neuro-Mechanical Link between Acceleration and Vmax

Duration to Reach 95% of Vmax for Elite is 4.5 to 5.0 Seconds

Step Length Increases Asymptotically Toward Vmax

Elastic Forces Predominate as Velocity Increases

Teaching and Coaching Pure

Acceleration

Wall Sprint Series - Neuro-muscular

Resisted Acceleration–Power

Acceleration Ladder – Neuro-muscular

Assisted Acceleration – Reactive Combo

Contrast Training - Combination

Wall Sprint Series

Stance

Body Position

Power Line Position

Ankle Dorsiflexion

Wall Sprint Stance (Faults)

Body Position Power Line Position Plantar Flexion

Wall Sprint Series

Ready Position

Knee Punch Forward

Ankle Dorsi-flexed

Sole of the Foot Down

Toe Behind the Knee

Shin Angles Parallel

Wall Sprint March Progression

Single Leg March

Wall Sprint March Progression

Alternate Leg March

One Count Wall Sprint

Knee Punch – Thigh Drive

Body Position

Ankle Cocked

Shin Angle

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Two Count Wall Sprint

Knee Punch – Thigh Drive

Body Position

Ankle Cocked

Shin Angle

Three Count Wall Sprint

Knee Punch – Thigh Drive

Body Position

Ankle Cocked

Shin Angle

Avoid Butt Kicking

Rapid Fire Wall Sprint

Knee Punch – Thigh Drive

Body Position

Ankle Cocked

Shin Angle

Harness Resisted Acceleration

Resisted A-Run

Acceleration

Contrast Acceleration

Bullet Belt Pop & Release

Resisted Acceleration Options

Face to Face Stance

Resisted Acceleration Options

Face to Face A-Run

Contrast Acceleration

Face to Face Release

Contrast Acceleration

Face and Chase

Acceleration Ladder

Start Stance

Acceleration Ladder

Execution

Transition Phase

Neuro-Biomechanics of Transition

Neuro-mechanical link between pure

acceleration and maximum velocity

mechanics

Common Faults

Stay in pure acceleration too long

Rush into maximum velocity too soon

“Drive Taller”

Main Area of Training Concerns

• Technique: The Ability to Efficiently Run at a Wide Range of Pace • Strength and Power: The Ability to Generate High Rate of Force Development • Metabolic Fitness: All Appropriate Energy Systems are Developed to Genetic Potential. • Energy Distribution: The Ability to Execute a Run Adjusting Under Varied Situations (Terrain, Weather, Pack Weight)