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Growth, Development and the Talented Athlete. Dr Craig S. Duncan Centre of Physical Activity Across the Lifespan Australian Catholic University. Overview. Growth and Development Injury Understanding success Take home messages. gender. long term medication. physical environment.
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Growth, Development and the Talented Athlete Dr Craig S. Duncan Centre of Physical Activity Across the Lifespan Australian Catholic University
Overview • Growth and Development • Injury • Understanding success • Take home messages
gender long term medication physical environment ethnic origin genes What influences growth? hormones pre-natal environment emotions activity nutrition
Growth before puberty • Similar in boys and girls • ~ 5 - 6 cm per year • ~ 2.5 kg per year • Girls slightly greater body fat
Pubertal growth GIRLS • Begins 9-10 y • Peaks at around 12 y • Growth rate slows • Slow growth until 16 -18 years BOYS • Begins 11-12 y • Peaks at around 14 y • Growth rate slows • Slow growth until 18 -20 years
Order of growth • Height first – (PHV)- 11 to 13 y in girls- 13 to 15 y in boys • Body weight - 7 kg gain in girls (fat free mass) (3 kg fat)- 14 kg gain in boys (fat free mass) (1.5 kg fat)
Different ages of development • Chronological age • Bone age • Pubertal age(self-reports)
Considerable variation • TIMING – onset of adolescent growth spurt • TEMPO – rate of progress through the spurt
Age of peak height velocity Malina et al. Am J Hum Biol. 1999, 11:189-200
Delayed growth through sport in females? • Most frequent: gym, dance, middle distance runners • Underlying mechanisms unclear • Alterations not common with <15 h/wk • Strong selection bias?
Late maturation in boys • Intensive training = energy drain • Growth may be slowed in runners • Growth rate during season may slow • Post season growth acceleration
Growth and Strength • Relative isometric strength (normalised for body mass) varies only slightly during childhood and adolescence • There does seem to be relative strength in boys after the age of PHV • Gender differences in relative strength of the upper extremity and trunk exist from age 7. • No gender differences in lower extremity strength. • Gender differences prior to puberty may be due to higher proportion of body fat and lower lean tissue mass in females that exists from mid-childhood onwards (Stolz & Stolz, 1951; Faust, 1977)
Growth and Strength • Linear increase in strength with CA from early childhood until 13-14 years in boys • Similar linear relationship in girls until 15 years • Acceleration in strength during male adolescence demonstrates the relatively small pre pubertal sex differences • Studies indicate that Isokinetic elbow and Knee extensor/flexor strength develop similarly in both genders until age 10-11 years • Isokinetic strength increase in boys consistently greater than in girls (post 10-11 years) • Extensor strength always > than flexor and this ratio with age (Jones, 1949; Malina, 1975; Parker et al. 1990; Asmussen, 1973; Malina, 1986; Alexander & Molnar; 1973; Gilliam et al.; 1979)
Increasing Strength with Training Children and adolescents can safely improve strength if • appropriate resistance training guidelines • are followed
Growth and Cardiovascular Endurance • Maximal oxygen consumption will improve as a function of age until 18-20 years • Differences between genders prior to puberty have been relatively unexplored • Reliability and reproducibility of VO2 max measures in children is questionable • Void in the literature in information concerning children <6 years • Linear increases exist from 7 years but when adjusted for body mass no consistent pattern emerges • Gender differences exist in absolute terms but when results are adjusted for body mass girls are nearly as good as boys • Males demonstrate an increase at puberty but a girls VO2max will decline from 12 years of age
Growth and Speed • Influenced by reaction time as well as movement time and reaction time improves with age • Cratty (1986) reported that it takes a 5 year old twice as long to react to an identical task compared to an adult • Linear increase in speed from 3-5 years - no gender difference • At 6-7 years boys and girls are similar in running speed • Boys superior from ages 8 to 12 • Both genders improve with age at a rate of approx. 30cm/second/year from ages 6-11 years • Speed of movement improves until age 13 in both genders than girls level off and males continue to improve
How much from our parents? • Body size • Body shape • Adult stature • Tempo of growth* • Timing and rate of sexual development • Skeletal maturation • Dental development Genetics 40 – 70%
Musculoskeletal injuries • Long bone growth • Strong ligaments • Avulsion /epiphyseal fracture more likely than ligamentous damage
Increases in young athlete injuries • Overuse injuries = new childhood disease • Overaggressive nature of organised youth sport • Eg stress fractures growth plate disorders frayed heel tendons vertebra slippage
Cause of overuse ???? • One sport • Early age • Yearly participation • Manic training • Training beyond body’s capacity • Same techniques, same drills, … over and over again
Lamenting losses • Loss of the generalist • Loss of the playground athletes • Parents who can see consequences of long term and irrecoverable damage • Curt Shilling factor • “What will they have for longer, the trophies or the injuries?” New York Times: Feb 2005.
Preventing Injuries • Mandatory coaching accreditation • At least 3 months off • Whole of body training • Deceleration and acceleration training • Flexibility • Balance • Biomechanically correct running and jumping
Case study • Jeret, 16 played 64 baseball games one summer – reconstructive elbow surgery • “I would tell kids coming up…. Don’t be such a hero. Take a rest” • “I look back now at all those games I won when I was 14 or 15. They don’t mean so much anymore. They weren’t worth it.” New York Times, Feb 2005
Talent development • Children decide to become elite athletes — not parents • Talent not always apparent by observation alone and not in one-off performances • Being a big fish in a big pond — not a big fish in a small pond • Keep expectations real
Crystal ball gazing Adolescent success ≠ adult success • Paula Radcliffe (12 yr) 299th – National Cross Country championships • Only 3 English soccer stars represented nation at every age level • Kieran Perkins - not in Under 14 team - under 15 national team • Lance Armstrong – swim practice at 12 yr - put in with 7 yr olds - next yr 4th in state 1500 m
Confuse achievement with potential • Need to ignore age-level rankings • Who looks like making it next time? • Need to identify people with the potential to grow • …… need a more complete package
A package of physical and mental abilities • To avoid injury • To train and compete harder • To control lifestyle issues • To sacrifice social opportunities
Success at an early age? • May not prioritise hard work on technique • May not see they have to work as hard • More advanced or more mature? • Have early successes increased motivation? • Better training environment? • Better equipment? • Better parental support? • DO THEY JUST HAVE THE CHARACTERISTICS TO MAKE THEM SUCCESSFUL NOW?
IOC consensus statement: ‘‘trainingthe elite child athlete” The entire sports process for the elite child athlete should be pleasurable and fulfilling Coaches, parents, sports administrators, the media and other parties concerned should limit the amount of training and competitive stress on the elite child athlete Parents/guardians should develop a strong support system to ensure a balanced lifestyle including proper nutrition, adequate sleep, academic development, psychological wellbeing and opportunities for socialisation Br J Sports Med 2008;42:163–164. doi:10.1136/bjsm.2007.044016
PHYSICAL HEALTH CV fitness Weight control Muscular strength Muscular endurance Flexibility Healthy bones PSYCHOSOCIAL HEALTH Citizenship Social success Positive friendships Leadership Initiative Positive career prospects Less antisocial behavior and school drop out Benefits should outweigh risks
Conclusion • THINK LONGTERM • Value your Athletes’ Motivation • Monitor Rating of Perceived Exertion • Value Social Aspects • Early Action on Pain • Find out about other Demands • ENJOY the JOURNEY
Contact Details • craig@athleticdevelopment.com.au • www.athleticdevelopment.com.au • www.athleticdevelopment.blogspot.com