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Puberty

Puberty. Normal Growth and Development. To assess the growth and development during puberty it is critical to evaluate the sexual maturity ratings as these correlate to normal growth and physiological changes .

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Puberty

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  1. Puberty Normal Growth and Development

  2. To assess the growth and development during puberty it is critical to evaluate the sexual maturity ratings as these correlate to normal growth and physiological changes

  3. Sexual maturity ratings include breast development in females and genital development in males • Pubic hair development in both males and females

  4. Key hormone • Growth hormone • Rise during puberty • Most marked during mid and late puberty and correlates best with pubertal stage, bone age and time from peak height velocity

  5. puberty • Both sex hormones and growth hormones participate in the pubertal gowth spurt • The ending of the growth spurth is secondary to epiphyseal closure due to action the sex hormones

  6. Growth velocity • 11 on boys • 9 in girls • varies

  7. Peak Height Velocity (PHV) • Mean of 13.5 in boys • 11.5 in girls

  8. Pubertal growth • 20 % of adult height • Average growth spurt lasts 24 to 36 months • PHV – females 9cm/yr males 10.3 cm/yr • Males are an average 12-13 cm taller than females primary because of the two delay in bone closure

  9. Weight • Weight velocity increases and peaks during the adolescence growth spurt • Pubertal weight gain accounts for about 50% of an individual ideal adult body weight • PWV highly variable

  10. Differences in Growth spurts between males and females • PHV occurs about 18-24 months earlier in females than in males • PHV in females averages 2cm/yr less than in males • PWV coincides with PHV in males but PWV occurs 6 to 9 months after PHV in females

  11. Prediction of mature height Girls • (Father’s height – 13cm) plus mothers height 2

  12. Boys • (Father height plus 13cm) plus mother height 2

  13. Lean Body Mass • Lean body masses decreases in females from about 80% to 75% at maturity • Males it increases from about 80% to about 90% at maturity due to the increase muscle mass • In females the percentage of body fat increases

  14. Skeletal mass • Increase in skeletal mass is critical • Epiphyseal maturation occurs under the influence of estradiol and testosterone

  15. Male Sexual development • Stage G2 • Average age of 11.6 • First physical sign of puberty in 98% of males is testicular enlargement

  16. Male Sexual Development • Adrenarche • Beginning of the growth spurt • Testicular development • Beginning of the pubic hair • Peak height velocity (PHV)

  17. Female Sexual Development • Breast Bud • Age decreasing 8.87 • Completion of puberty average 4 years but can range 1.5 to 8 years • Growth spurt starts one year before breast development • 1.1 years until PHV • Followed 1 year of menarche

  18. No correlation between adult height and either age of onset of growth spurt , age of PHV, velocity at peak, or pubertal height gain • Correlation between adult height and the height at onset of growth spurt or height at PHV

  19. Peak Height Velocity (PHV) • PHV in girls is about 11.7 and in boys it is 13.6 • Girls accelerate about 2 years earlier than boys • 90% of both male and females are within 2.5 cm of their final adult height 3 years after their growth peak

  20. Scoliosis • PHV plus 3.6 years • PHV is identified you can predict how long to wear the brace • More than 9 cm per year 90% in PHV • 30 curve at PHV probable surgical

  21. Growth plates • If iliac apophysis is visible 85% chance the patient is at or just beyond the PHV

  22. Biceps/Quadriceps Strength • Girls – related to height and weight • Boys related to height and weight and testosterone

  23. Developed at PHV • Balance • Speed of limb movement • Trunk strength • UE muscle endurance • Explosive strength • Running speed • Agility • Cardiovascular endurance • Anaerobic capacity

  24. PHV vs Age • Early maturity boys more successful in sports • Strength and power attain maximum growth after PHV • Running speed before PHV

  25. Biological Maturity • The prime indicator of biological maturity is the age at which children go through their main adolescent growth spurt which is known as Peak Height Velocity (PHV). • For girls Peak Height Velocity can occur between the ages of 9 and 15 (average 12 years) while for boys it occurs on average at 14 years but can be as early as 11 and as late as 17 years (Astrand 1992). • This means that adolescents born in the same year can be up to 5 years apart in biological age depending upon whether they are early, average or late maturers. • Late maturing boys, in particular are at a physical disadvantage to their early maturing peers for most of their teens because strength and stamina - only develop to adult levels after PHV.

  26. Selection Bias and Early Maturing Adolescents • Sport development systems compound the late maturer’s early disadvantage by become increasingly selective just when maturational levels create the biggest differences in physical abilities often resulting in coaching and other resources being concentrated on the wrong athletes. • A 2004 study (Suslov & Kukalov) on Russian athletes aged 12 to 15 training in regional teams found that about 40% of the sample was comprised of early maturers, significantly more than their distribution in the general population, while only 20% of the girls and 26% of the boys in the sample were late maturers. • The researchers concluded that despite knowing that the adult performances of late maturers surpass those of early maturers many coaches were not taking into account the biological age of the athletes and were simply selecting taller, heavier athletes at every age level. Our subliminal programming to select for superior physical abilities at every age can be hard to overcome.

  27. Late Maturers • Late maturers may be discouraged if they perceive themselves to be less talented than their early maturing peers, while early maturers may themselves drop out if they become discouraged in later adolescence as their early advantage in terms of strength and stamina disappears once maturity levels have evened out and their performances subsequently plateau or decline.

  28. Name this Person

  29. Most Talented • In many instances those who look talented at an early age often aren’t while the true superstars emerge late. • Michael Jordan the basketball great was 17 and in his penultimate year of high school before he succeeded in gaining a place on the varsity basketball team. • A late maturer, he’d grown 10cm since he’d been cut from the team for being too short the previous year. Michael Jordan illustrates the true lesson of the parable of the Talents – where many others would have dropped out he said that not making the cut made him work harder and taught him that if you set goals and put in the work, hard work pays off.

  30. What is RAE?

  31. Relative Age Effect (RAE) • Research has supported this statement, showing that the month in which a child is born, as it relates to the cut off date for the age group, can have an effect on the child’s success in some sports. This is termed the relative age effect (RAE). • A variety of studies have shown that the RAE exists in soccer, hockey, baseball, college football, cricket and tennis. It has been shown that up to 81% of the players had a birthday in the first half of the year (4). A recent study examining the US soccer Olympic Development Program (ODP) found that in one group of boys, 70% had a birthday in the first six months of the year (5). • It is hypothesized that the RAE is due to the physical and psychological advantage that the older player has in addition to the opportunity to have gained more sport-specific experience (4).

  32. Relative Age Effect • Glamser and Vincent (5) explain why this is so critical: • In the initial stages of the selection of young athletes, a 6 to 12 month developmental advantage can be decisive. Slightly older participants tend to possess physical and psychological advantages that make their selection more likely. • Once young players are selected for elite sport participation, they are taught the correct skills and techniques, while being socialized into appropriate attitudes for later success by capable coaches. • This specialized socialization process is not experienced by players not selected for elite teams. • The absence of this early experience puts younger players who were not initially selected at risk of non-selection at subsequent player evaluations. Over time, this disadvantage builds. (p. 2)

  33. When do injuries occur in youth sports?

  34. Summary

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