Part 4 - Optimal sequential timing

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En provenance du cours de University of Florida

The Science of Training Young Athletes

163 notes

University of Florida

The Science of Training Young Athletes

163 notes

Seventy percent of kids drop out of sports before their high school graduation. Only 15% leave because they feel they are not good enough. Almost 70% leave because they were not having fun, or due to problems with the coach. Injuries cause 30% to give up sports. This course is packed full of practical sports science information that provide youth coaches and parents with the practical pediatric sports science insights to successfully retain young athletes and develop their sport potential while avoiding injury and overtraining. We begin by examining the multidimensional nature of coaching, the relevant sport motor performance abilities, the impact of growth and development on motor skills, the gene versus practice controversy, and briefly overview the body structures strengthened through training. Then we explore the athlete's energy supply, where this energy comes from, and how it matures along with the athlete. Finally, we examine the development of strength, power, anaerobic capacity, coordination and flexibility through the life span. The optional text manual for this course is available at: http://www.learnitez.com/HighPerformanceScience/manuals/

À partir de la leçon

Week 5: Enhancing the fluidity of movement

Coordination and flexibility permit movements that are precise, fluid and spatially controlled. In this section we examine current knowledge about coordination and flexibility as the young child moves through early childhood and into adolescence.

Part 1 - Introduction to coordination4:19

Part 2 - Brain motor control areas4:19

Part 3 - Coordinating variables6:10

Part 4 - Optimal sequential timing6:40

Part 5 - Soccer example of coordination & control5:19

Part 6 - Learning control3:18

Part 7 - Key points of coordination2:27

Rencontrer les enseignants

Dr. Chris Brooks
Instructor
Coaching Science Coordinator for USA Track and Field

There's an optimal coordinated pattern to performing movement units of all skills.

Some seemingly diverse skills for have a common goal such as launching and

implement, have a similar optimal movement pattern.

Throwing and striking for example,

involve roughly the same order of moving the appropriate body parts.

The sequence begins with the ground and feet and

then the hips followed by the shoulders the arms.

And then the hands with the implementers finally ejected it's a bit like launching

a satellite on top of a five stage rocket the hardest work is done immediately

at launch and for this reason the biggest thrust of force is needed for this stage.

When throwing or hitting the legs are analogous to the rocket's main stage

to provide the initial force for setting the entire mass of the body into motion.

Stage two are the hips, stage three is the shoulders,

stage four the arms and stage five the hand.

Each sequential body part is slightly lighter than one preceding it.

The precise timing of the forces produced at each stage sum together to

produce the final high velocity needed to project the implement toward its target.

Now, this chart here illustrates the correct sequence of body movements for

a baseball swing.

The correct sequence includes hip rotation first, and this is followed by

shoulder rotation, and then, the arm, and finally wrist extension.

A bad swing begins with shoulder rotation and

then hip rotation, and then extension.

And this is a common pattern seeing with novice staff, athletes.

The tennis serve, the golf swing, and throwing all use the same

sequence of hips first, shoulder, and then arm extension.

However, coordinating the correct sequence of body parts is just

one aspect of performing a skill effectively.

There is also a control component.

Performing the correct relative pattern of body parts and

movement units is the coordination aspect.

And optimizing the motor unit firing so the velocity of each body part is summed

at each stage to ensure maximum velocity at the final stage is just as important.

And this is the control component, an effective

outcome of a skill requires both coordination and control.

The counter movement vertical jump provides an example of how both

coordination and control is used to maximize the jump.

This jump begins with a downward motion and this is followed by the vertical jump.

So here's the counter movement.

And this is the propulsion phase.

The correct relative motion between the body segments for

the counter movement vertical jump begins with simultaneous flexion of the hips,

knees and ankles in the counter movement phase.

And this is followed by simultaneous extension of the hips, knees and

ankles in the propulsion phase.

Now a normal three to four year old child can easily perform the sequence

when asked to jump really high when starting from a standing position.

However, a child lacks the muscular control, and is unable to precisely

time motor unit firing to produce maximum takeoff velocity.

A more skilled performer can optimize body segment movement so

that velocity at takeoff is maximized.

And therefore the height jumped is maximized.

And for this to happen, two things must occur.

The first is to ensure a maximum center of gravity height at takeoff.

And this is H1 in this graphic.

And this occurs if the range of motion of the hips, knees, and

ankles is maximized during the counter movement phase to optimize

the time of force application against the ground.

The second is to obtain maximum vertical velocity of

the center of gravity at the very instant of takeoff.

And there's a direct relationship between takeoff velocity and

how high the center of gravity lifts off the ground.

The height the center of gravity rises off the ground is indicated here by H2.

And this in turn is dictated by the strength of the extensor muscles of

the hips, knees, and ankles.

The longer the time producing the force, the higher the takeoff velocity will be.

Time of force application depends on the extent to which the available

range of motion of the hips Knees and ankles as used.

A restricted range of motion adversely affects the ability of the athlete

to produce vertical forces.

And the result is a lower than optimal jump height.

When comparing children with experienced athletes,

there's no difference in the coordination variables.

However, there are significant differences in the control variables.

Children are not able to optimize motor unit firing pattern

to achieve the ultimate goal of maximizing their jumping height.

A comparison of highly skilled athletes with

lesser skilled athletes reveals the same pattern.

There is no difference in their coordination, that is their ability

to perform the correct sequence of movements are the same.

Their performance difference is due to the inability of the less skilled

athlete to optimize the relative motion of the body segments due to

ineffective motor uniform firing patterns within the appropriate muscles.

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