Part 2 - Ontogeny

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Do curso por University of Florida

The Science of Training Young Athletes

205 classificações

University of Florida

The Science of Training Young Athletes

205 classificações

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/

Na lição

Week 2: Strategies for maximizing the athlete’s potential

Many factors can positively and negatively impact the young athlete’s ability to optimize their sports potential. In this section we examine strategies for ensuring the athlete’s systematic long-term sports development and how to mold the correct sport-specific phenotype.

Part 1 - Introduction to critical training periods1:58

Part 2 - Ontogeny7:59

Part 3 - Development and environment6:39

Part 4 - Motor circuitry development5:40

Part 5 - Periods of accelerated growth6:58

Part 6 - Key points of critical training periods3:57

Conheça os instrutores

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

To fully understand the evolving nature of the child's physical work capacity and

exploitation capabilities, and to therefore the quality of their

sports performance, we must venture into the field of ontogeny.

Now ontogeny is a branch of biology that examines how an organism

slowly evolves from an embryo all the way through to an adult.

And then the case of the young athletes, the magnitude and

multitude of the dramatic changes in shape and physiology of their body as

they evolved into an adult is noticeable in the quality of the sports performance.

Understanding the maturation of the child from the perspective of ontogeny,

potentially provides a better indicator for identifying

future early talent than the more common champion model that's currently used,

and the champion model it assumes that children are simply miniature adults.

And assesses this port talent by looking at how closely they resemble of

physique and motor performance abilities of an elite athlete.

Indeed, it is really really tempting to take this view,

because we know from simple observation that children do get bigger with age.

External changes reflect internal changes.

A 16 year old boy for example, has lungs and

oxygen capacity almost three times larger than it was when he was five.

His heart is 2.7 times bigger that it

was 95 grams at 5 and it is 258 grams at 16.

A girl has tripled the grip strength at 16 than she had when she was age 5.

Her muscle mass increases from 7 kilograms to 23 kilograms.

And the longer leg length allows a 16 year old to run faster and with fewer strides,

resulting in a lower oxygen requirement than a five year old must have.

In other words, there is no question a child is smaller than an adult.

And we also know that the child will eventually become an adult, and

it doesn't take much brain power to figure this out, but this miniature adult

view ignores how the body evolves into the adult form.

It doesn't tell us what happens if the environmental conditions in which

the child is growing is not conducive for

allowing maximization of a genetic potential.

Ontogeny provides these insights by explaining

how the structures increase in size and

their rate of growth by taking the environmental conditions into accounts.

The body structures and physiology of a child do not evolve

into an adult form at a uniform rate nor

do all the potential elite athletes have the correct environmental conditions

as a child to ensure successful evolution into an elite athlete.

So let's just take another look at this chart, and we can see that there

are periods of unstable transitions consisting of both progressions and

regressions, lodged between short periods of stability.

And this explains why a child's performance will accelerate at times, and

in other times it will stabilize.

And in other times, it will regress.

And if you happen to be coaching a child who is in the regression phase,

both you and the child will equally frustrated

if you don't understand why this regression might be occurring.

Now research on the leg stiffness of

children nicely illustrates this phenomenon.

When landing while running or

jumping the touch down knee will bend slightly as it catches the body weight.

The amount of bend provides an indication of leg stiffness.

The less the bend,the stiffer the leg.

And the yellow circle here indicates the knee bend phase of this runner as

his body weight is moving over the knee so the leg can push off for the next stride.

The leg stiffness study used boys between ages 7 to 16 years of subject

to explore how the stretch shortening cycle responded as they aged.

In the stress shortening cycle is an active stretch of the muscle

followed by an immediate shortening.

And the runner's thigh muscles here will stretch as they catch the weight of

the body, and then, they will contract to accelerate the body forward.

The same thing happens to the calf muscle and the Achilles tendon.

The stretch shortening mechanism is fundamental to running and jumping and

is a factor in leg stiffness.

In the study, the young athlete's reactive strength was assessed

using a hopping test involving five maximal vertical hops

on a contact mat that was able to measure the contact time and the flight time.

And the boys were instructed to maximize jump height and

minimize ground contact time.

And then an equation was used to assess leg reactive strength, and

this equation was reactive strength, is equal to the jump height and that was in

millimeters divided by the ground contact time, and that was in milliseconds.

So, let's go back and take a look at the graph of the data.

The black dotted line is the speed of growth

of the child that we discussed in the previous module.

And the red dotted line represents the leg reactive strength index.

And the index actually indicates how quickly the stretch sensors and

the muscle and the tendon react to maintain leg stiffness.

Now stiffness of the leg is reflected in the knee bend upon landing.

And a small knee bend is desirable because a stiff leg allows for

faster speed and higher jumps.

Now notice how reactive strength increases linearly between age 9 until about age 10.

And then there is an accelerated increase between age 10 and 11.

And then between age 11 and 12, there is a decline in leg stiffness.

And this decline occurs immediately before the growth spurt.

Now in this area corresponding to the growth spurt,

there is an increase in leg stiffness.

And this increase in leg stiffness continues until age 16 years.

And it so happens that endurance, speed, and

strength all show a similar fluctuation between accelerated improvement,

followed by decline, and then followed by an accelerated improvement again.

And the question is what on earth is going on here?

And we're going to come back and answer those questions shortly after we examine

another concept related to critical and

sensitive periods of a child's development.

And this concept is the notion of windows of opportunity.

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