20/02/2016

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ProfessorAaronCouttsPhDUniversityofTechnologySydney,Australia

FactorsAffectingTalentIdentification&AthleticDevelopmentinYouthSports

@aaronjcoutts

@tomlovell26

TomLovell

Overview

• Model for talent identification (TID) and development (TDE)

• Relative‐age effects in team sports

• Studies examining TID and TDE in lower level youth sport1. Factors related to initial sport selection2. Factors related to team selection (within age groups)3. Factors related to position in a team4. What influences technical / tactical performance in match play5. Factors influencing performance trajectories during youth

• Discuss how these may affect development

Older, Early Maturer

Younger, Late Maturer12 months

TalentIdentification

WORSTCASEOUTCOME!

Quarterly birth data distributions, Australian U20 team (2008 – 2011) and players competing in the National U16 Championships (2004 – 2007).

0

5

10

15

20

25

30

35

40

Under 20s Under 16s ABS Data

Per

cen

tag

e %

Q1 % Q2%

Q3% Q4%

RelativeAgeEffects:SelectionBias

Potential Bias in Australian Rugby Development Pathway (2004 – 2011).

RelativeAgeEffects&Selection‘Bias’

80% National U20 team identified at 15 years old!

Good Section or Poor Deselection?

BIAS

Figure 2: A) Quarterly and B)  Half‐yearly distribution of birth‐date for AFL National Draftees from 2001‐2012. 

0%

5%

10%

15%

20%

25%

30%

35%

40%

Q1 Q2 Q3 Q4

Proportion of Po

pulation

Quarter

Adolescent

Mature Age

0%

10%

20%

30%

40%

50%

60%

70%

H1 H2Half

CONFIRMS BIAS!

MESSAGE: Don’t give up!

We are missing talent with youth selection processes

RelativeAgeEffects&Selection‘Bias’

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TalentIdentificationIssues

• Relatively older, more mature individuals are more frequently selected into elite youth team sports  [Cobley et al. 2009]

• Physical characteristics differentiate young players between playing levels in youth team sports [Vaeyens et al. 2006, Till et al., 2014]

• Relative age effects appear strong mediators of selection bias ‐ this persists through the talent pathway

• Where & why does this bias start?

Talentidentificationanddevelopment

Identification Selection

Development

Detection

(Williams & Reilly, 2000)

1. Sport Choice

2. Team Selection

4. Developmental Trajectories

3. Physical and Technical Match 

Activity

TalentDetection

1.SportsChoiceinaYouthPopulation

Factors such as maturity and physical profile may orientate an individual towards certain sports activities.

This may affect the opportunities provided for talent development and team selection. 

MethodA cross‐sectional, cohort study of 1076 boys aged 8‐17 y.

• Sports choice• Sports participation history• Anthropometric, physical and coordination characteristics• Academic ability

Athletics

Australian Rules Football

Badminton

Baseball

Basketball

Cricket

Cross Country

Cycling

DanceDiving

Fencing

Fitness TrainingFootball

Golf

Gymnastics Karate

Martial Arts

Mountain Biking

Orienteering

Rugby

Sailing

Shooting

Snow SportsSquash

Surf Lifesaving

Surfing

Swimming

Tennis

Volleyball

Water Polo

14

16

18

20

22

24

26

28

10 11 12 13 14 15 16

Body Mass Index

Chronological Age (yrs)

SportxAgexBMIxParticipants

PhysicalProfilesinYouthSport

n = 1075

Basketball

CricketFootball

Other

Rugby

Swimming

Tennis

18

19

20

21

22

13.0 13.5 14.0 14.5

Body Mass Index

Chronological Age (yrs)

SportxAgexBMIxParticipants

PhysicalProfilesinYouthSport

n = 1075

No sig differences

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Basketball

Cricket

Football

Other Rugby

Swimming

Tennis

156

158

160

162

164

166

168

170

172

48 50 52 54 56 58 60

Heigh

t (cm)

Body Mass (kg)

SportxHeightxBodyMass

PhysicalProfilesinYouthSport

n = 1075

Height F = 2.35, ES = 0.03, p = .030Body Mass F = 3.18, ES = 0.04, p = .005

**†

*†

* *

† Different from Rugby

* Different from Basketball

Seem to be choosing sports based on physical 

characteristicsBasketball

Cricket

Football

Other

Rugby

Swimming

Tennis

94

96

98

100

102

104

106

108

1,100 1,200 1,300 1,400 1,500 1,600

Coordination Test (AU)

Aerobic Fitness Test (m)

SportxFitnessxCoordination

PhysicalProfilesinYouthSport

n = 499

Coordination F = 5.24, ES = 0.06, p < .001Aerobic Fitness      F = 4.60, ES = 0.05, p < .001

*†*†

*†*

† Different from Rugby

* Different from Football

*

Popular sports tend to be chosen by fitter more 

coordinated 

0

500

1,000

1,500

2,000

2,500

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000

Aerobic Fitness Test (m)

Total Training (hours)

LevelxFitnessxTrainingHours

Recreational

Representative

PhysicalProfilesinYouthSport

Aerobic Fitness      F = 47.02, ES = 0.11, p < .001Training Hours       F = 27.04, ES = 0.07, p < .001

n = 371

Representative youth athletes are fitter and 

train more

TakeHomeMessage#1

• Physical characteristics may orientate an individual towards certain sports

• This may affect an individual’s opportunities provided for development (preferential resource allocation) and team selection

• HOWEVER, since youth physical advantages may not be retained into adulthood, young athlete should be encouraged to sample a diverse range of sports and skills

TalentIdentification&Selection

PlayingPosition

PlayingLevel

Anthropometry Physical CapacityTechnical AbilityMotor Competence Maturity offset

Physical

Technical

Total distanceHigh speed runningSprintsAccelerations

Skill Involvements

AttackerMidfielderFullbackCentral Defender

Team 1Team 2Team 3

Overall rankTechnical rankTactical rankPhysical rank

Psychological rank

CMJ, Standing broad jump, Sit‐and‐reach, Handgrip strength, Chin‐up test, 20 & 30‐m sprint, RSA test, T‐test, Power throws, YoYo IR1, KTK test

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2.TeamSelectioninaSchoolProgram

When identifying talent for team selection, relative age, maturity and physical characteristics may all influence a coach’s perception of performance and “potential”.

While this has been shown at an elite level, it is likely this phenomenon originates as the grassroots level.

MethodA cross‐sectional, cohort study of 180 soccer players aged 10‐18 y.

• Playing level and playing position selection• Anthropometric, physical and coordination characteristics• Coach rating of player ability

PlayingPosition

PlayingLevel

AnthropometryPhysical CapacityTechnical AbilityMotor Competence

Physical

Technical

Total distanceHigh speed runningSprintsAccelerations

Skill Involvements

AttackerMidfielderFullbackCentral Defender

Team 1Team 2Team 3

Overall rankTechnical rankTactical rankPhysical rank

Psychological rank

FactorsaffectingteamselectionPhysical‐ &coordination‐relatedfactors

‐1.0

‐0.5

0.0

0.5

1.0

Maturity Offset

Height

Body Mass

Sit and Reach

Vertical Jump

30 m Sprint

T‐Test

YoYo IR1

Dribble Test

KTK

Team 1

Team 2

Team 3

Difference between playing levels

*

*

**

**

**

‐1.0

‐0.5

0.0

0.5

1.0

Maturity Offset

Height

Body Mass

Sit and Reach

Vertical Jump

30 m Sprint

T‐Test

YoYo IR1

Dribble Test

KTK

Attackers

Midfielders

Fullbacks

Central Defenders

FactorsaffectingpositionselectionPhysical‐ &coordination‐relatedfactors

Difference between playing positions

*

*

*

**

Playing Position ANOVA

Attackers Midfielders Fullbacks Central Defenders Effect size F p

Team 1 n = 25 n = 16 n = 16 n = 18

Overall Rank 5.0 ±3.2 3.2 ±2.8 7.0 ±3.7 4.8 ±2.5 0.15 4.296 0.008 *

Tactical Rank 4.8 ±3.8 2.9 ±2.5 7.3 ±3.3 4.8 ±2.6 0.19 5.486 0.002 *

Technical Rank 5.4 ±3.5 2.9 ±2.2 6.8 ±3.4 5.6 ±2.7 0.17 4.875 0.004 *

Physical Rank 5.0 ±3.2 4.3 ±3.7 6.8 ±2.7 3.7 ±2.5 0.11 2.897 0.041 *

Psychological Rank 5.5 ±3.2 3.4 ±3.0 5.3 ±3.1 3.7 ±2.4 0.09 2.310 0.084

Team 2 & 3 n = 44 n = 43 n = 26 n = 26

Overall Rank 4.9 ±3.6 5.6 ±3.6 5.5 ±4.7 5.9 ±3.9 0.01 0.380 0.767

Tactical Rank 5.2 ±3.5 4.6 ±3.6 6.0 ±4.7 5.7 ±4.1 0.02 0.756 0.521

Technical Rank 5.3 ±3.2 4.7 ±3.7 5.1 ±3.3 6.2 ±4.1 0.02 1.008 0.391

Physical Rank 4.7 ±3.6 6.2 ±3.9 6.0 ±3.3 5.1 ±4.3 0.03 1.381 0.251

Psychological Rank 5.9 ±4.2 5.4 ±4.3 5.2 ±4.9 4.7 ±4.4 0.01 0.434 0.729

Data are means ± standard deviations; * = p < .05; ** = p < .001

Selected; Team 1 players, Non‐Selected; Team 2/3 players, Rank; subjective coach rating expressed as within‐team rank

FactorsaffectingpositionselectionCoachRatingsinTeam1players

Difference between playing positions

%Predicted

%Improve

%

Team 1 36.5 72.4 35.9

Team 2 37.1 50.8 13.7

Team 3 26.4 73.8 47.4

Total 33.3 64.8 31.5

FactorsaffectingteamselectionPhysical‐ &coordination‐relatedfactors

Discriminating between playing levels

• Technical ability• Aerobic Fitness• Sprint Speed• Coordination• Agility

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TakeHomeMessage#2

• Physical skills, technical ability and coordination play vital roles in determining playing level in youth soccer

• Maturation and anthropometry seem to guide young players towards particular playing positions

• While the coach’s selection processes are often performance‐oriented, this may impact the developmental opportunitiesprovided to young players

PlayingPosition

PlayingLevel

AnthropometryPhysical CapacityTechnical AbilityMotor Competence

Physical

Technical

Total distanceHigh speed runningSprintsAccelerations

Skill Involvements

AttackerMidfielderFullbackCentral Defender

Team 1Team 2Team 3

Overall rankTechnical rankTactical rankPhysical rank

Psychological rank

3.Physical&TechnicalMatchActivity

Both individual (fitness) and contextual factors (playing level and position) may influence match activity profiles in youth soccer.

It is therefore important to understand what factors may influence match performance and development opportunities in youth soccer.

MethodA cross‐sectional, cohort study of 180 soccer players aged 10‐18 y.

• Mixed‐model approach• Various match‐related and individual player factors• Physical and technical match activity

MatchActivityProfilesAccountingforContextualFactors

Table 1: Covariates included in model specification.

Level of Data Factors Type Classification

Level 3 Cluster of clusters (random factor) Team

Level 2 Cluster of units (random factor) Player

Covariates Aerobic fitness Continuous YoYo IR1 distance (m)

Sprint speed Continuous 30 m sprint (s)

Total distance (Model 3) Continuous m∙min‐1

Level 1 Unit of analysis Individual match sample

Dependent variables Total distance (Model 1) Continuous m∙min‐1

High‐speed distance (Model 2) Continuous m∙min‐1

Skill involvements (Model 3) Continuous inv∙min‐1

Covariate Position Categorical ATT, MF, FB, CD

‐5.6%

‐7.6%

‐13.6%

7.0%

1.7%

‐0.8 ‐0.6 ‐0.4 ‐0.2 0.0 0.2 0.4 0.6

Effect Size

TotalDistance

MatchActivityProfilesAccountingforContextualFactors

Attacker

Fullback

Central Defender

Aerobic Fitness

Sprint Speed

Attacker

Sprint Speed

Central Defender

Aerobic Fitness

98.8 m/min 17.5 m/min

11.3%

‐22.2%

26.0%

5.2%

‐0.6 ‐0.4 ‐0.2 0.0 0.2 0.4 0.6 0.8

Effect Size

HSRDistance

• Both fitness and playing position influence match running in youth soccer

‐25.4%

‐21.8%

‐27.3%

0.8%

‐0.8 ‐0.6 ‐0.4 ‐0.2 0.0 0.2 0.4 0.6

Effect Size

SkillInvolvements

MatchActivityProfilesAccountingforContextualFactors

Attacker

Fullback

Central Defender

Distance (m∙min‐1)

0.37 inv/min

• Both playing position and match running influence skill involvements in youth soccer

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TakeHomeMessage#3

• A variety of individual (fitness) and contextual (position) factors influence match activity profiles in youth soccer

• These variations in match activity should not be confused with soccer performance

• Position selection may have considerable implications for developmental opportunities provided in youth soccer TalentDevelopment

4.Developmenttrajectoriesinyouthsoccer

Factors such as growth, development and training, make one‐off, long‐term predictions of future performance unreliable.

It is therefore important to observe the rate of improvement in performance skills, as well as current performance.

MethodA three‐year longitudinal, follow‐up study of a cohort study of 226 soccer players aged 10‐18 y.

• Mixed‐model approach• Various individual and contextual factors• Development of performance characteristic

@tomlovell26

TomLovell

Conclusions

1. Physical characteristics may guide young individuals towards certain sports, playing levels and playing positions in youth sport

2. These could have considerable implications for developmental opportunities throughout adolescence

3. Young individuals should be provided the chance to sample a wide range of sports and positions through their development to maximise learning opportunities

FutureConsiderations

1. Delay selecting into ranked teams?• Prevents deselection• Prevents early specialisation

2. Biological vs. Chronological ‘age groups • Biobanding training and competition

3. Continue with systematic benchmarking• Multi‐dimensional approach

4. Develop ‘smarter‘ (de)selection tools

5. Maximize participation through to complete maturation

Thankyou!