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GROWTH, DEVELOPMENT AND THE YOUNG ATHLETE

GROWTH, DEVELOPMENT AND THE YOUNG ATHLETE. Growth - Increase in the size of the body Height and Weight Exercise, adequate diet - essential for proper bone growth. Exercise affects primarily bone width, density and strength, no effect on length.

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GROWTH, DEVELOPMENT AND THE YOUNG ATHLETE

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  1. GROWTH, DEVELOPMENT AND THE YOUNG ATHLETE Growth - Increase in the size of the body Height and Weight Exercise, adequate diet - essential for proper bone growth. Exercise affects primarily bone width, density and strength, no effect on length. BONES formed through ossification - spread from primary (diaphysis) and secondary (epiphysis) ossification centers. INJURY at epiphysis could cause early termination of growth. Competitive sports (baseball, soccer) - greatest risk for epiphyseal injury.

  2. MUSCLE - growth accomplished by hypertrophy of individual muscle fibers ( myofilaments, myofibrils) muscle length - addition of sarcomeres and increase of length of existing sarcomers. Muscle mass peaks in females between 16 - 20 years, in males 18 - 25 years. • FAT - increase the size of existing fats cells, and increasing the number of fat cells. Amount of fat depends on: diet, exercise, heredity at birth - 10 – 12% total body weight is fat. At maturity 15% in men, 25  in female. • NERVOUS SYSTEM - myelination of the nerve fibers - necessary for fast reaction and skilled movements.

  3. PHYSICAL PERFORMANCE IN YOUNG ATHLETES • Motor Ability - INCREASES UNTIL 18 YEARS of life, girls usually plateau around puberty ( estrogen levels  greater fat deposition, more sedentary lifestyle). • Strength - improves - muscle mass increase with age, dependence also on neural maturation (limited until myelinization completed) • Pulmonary Function -  all lung volumes until growth completed, PEFR also increases. VE max - 40 - 60 l/min for 4 - 6 year-old boys - 110 - 140 l / min at full maturity

  4. CARDIOVASCULAR SYSTEM • Blood Pressure - directly related to body size • DURING EXERCISE – Lower SV - compensation by  HR. a-v O2 difference increases. • MAXIMUM HR higher - decrease with age (210 - 195 min from 10 to 20 years).

  5. Aerobic Capacity • VO2 max peaks between 17 - 21 in boys, 12 - 15 in girls. • VO2 max relative to body weight - no difference to adults (performance is far inferior to adults, difference in economy of effort).

  6. Anaerobic Capacity Lower in children -  glycolytic capacity because of  amount of phosphorfuctokinase. Anaerobic mean and peak power outputs lower in children

  7. Thermal Stress Children - more susceptible to heat and cold induced illnesses or injury lower capacity for evaporative heat loss, sweat less. Greater conductive heat loss  greater risk for hypothermia in cold.

  8. Training in Young Athlete • Resistance (Strength) Training • Resistance training - stronger, broader, compact bones. Training programs similar to adults program. Gains of strength by: improved motor skill coordination, increased motor unit activation, other neurological adaptations

  9. Aerobic and Anaerobic Training • Aerobic training does not alter VO2 max as much as would be expected (possibly because of small heart -  SV,  CO). Anaerobic capacity  with anaerobic training. • REGULAR TRAINING results in:  total body fat, fat-free mass,  total body mass. • GROWTH AND MATURATION NOT SIGNIFICANTLY ALTERED BY TRAINING.

  10. AGING AND THE OLDER ATHLETE • Sport Performance • Physical Prime - during 20 s or early 30 s. • Running Performance • Decrease with age, not dependent of distance. • Swimming Performance affected by aging in much the same manner as running.

  11. Peak Performances in both strength and endurance events decrease by about 1 - 2  per year, starting between 20 - 35. • Cardiorespiratory Endurance And Aging VO2 max decreases by about 10  per decade, starting in late teens in women and mid-20s for men, associated with decrease in cardiorespiratory endurance activity.

  12. Decrease in VO2 max is not strictly a function of age - athletes continuing with training - significantly less decrease in VO2 max. With aging - more sedentary life, gain weight. • Respiratory Changes With Aging  VC, RV,  RV/TLC - less air exchange with each breath. VE max decreases (loss of elasticity of lung tissue and chest wall) a-v O2 diff decreased -  O2 extraction by muscles (reduction of blood flow to muscle)

  13. Cardiovascular Changes With Aging • Maximal HR decreases - 1 beat per year (HR max  220 - age) SV and CO decrease with age  HR max - decrease in sympathetic nervous system activity  SV -  TPR (reduced compliance of arteries,  EF of left ventricle)

  14. ALL CHANGES MINIMIZED BY TRAINING CONTINUATION • MAXIMAL STRENGTH reduced with aging ( physical activity,  muscle mass - reduced protein synthesis, loss of FT motor units). • Training - lessen the impact of aging on performance (can´t arrest the process of biological aging). • Older people LESS TOLERANT OFENVIRONMENTAL STRESS. Aging reduces thermal tolerance ( sweat production).

  15. Body Composition With age - BODY FAT, ↓ FAT-FREE MASS  reduction in general activity levels. • CAUSES: dietary intake, physical activity, reduced ability to mobilize fat. TRAINING can held these chances in body composition. • ENDURANCE TRAINING IN OLDER INDIVIDUALS  muscle´s oxidateve enzyme activities,  muscle strength, muscle hypertrophy.

  16. GENDER ISSUES, FEMALE ATHLETE Body Size and Composition Until Puberty - no differences in body size and composition. At Puberty - estrogen -  fat deposition (hips, thighs,  rate of bone growth - final length earlier) Responses to Exercise Women - weaker (lower quantity of muscle, smaller muscle fiber cross - sectional area). Lower SV, Higher HR and SIMILAR CO for the SAME RATE OF WORK.

  17. Lower SV - smaller LV and lower blood volume (smaller body size). • VE max lower, mostly below 125 l/min (highly trained till 250 l/min). • VO2 max - lower when expressed in ml.kg.min. (extra body fat, lower HB leverls - lower oxygen content in arterial blood)

  18. Highest VO2 max for female - 77 ml. kg. min and 94 ml. kg. min FOR MEN • a-v O2 diff. - less increase - lower HB content, less O2 delivered to active muscles anaerobic threshold - little or no difference.

  19. Physiological Adaptations to Training • Women gain LESS FAT FREE MASS, INCREASE IN STRENGTH (20 - 40 ) in resistance training (due more to neural factors - increase in muscle mass small). Cardiovascular and respiratory changes accompanying ENDURANCE TRAINING - NOT SEX SPECIFIC.

  20. Athletic Ability • SPECIAL CONSIDERATIONS unique to female: menstruation, pregnancy, osteoporosis, eating disorders environmental factors.

  21. Menstruation and Performance • Considerable INDIVIDUAL VARIABILITY in performance during different phases of menstrual cycle (no change x noticeable), no general pattern in achieving BEST PERFORMANCE during any specific phase. Women experiencing PREMENSTRUAL SYNDROM or DYSMENORRHEA - performance decrease. • MENARCHE - coming later in highly trained athletes - not as a rule

  22. Menstrual Dysfunction • Disruption of normal menstrual cycle. • A high percentage of female athletes in endurance and appearance sports experience SECONDARY AMENORRHEA - normal menstrual function lost for months or years. • REVERSIBLE - reduction in intensity and volume of training, increase in caloric intake

  23. Pregnancy • During exercise - major concerns - risk of FETAL HYPOXIA (reduced blood flow to uterus), • FETAL HYPERTHERMIA ( of mother´s internal body temperature),  CARBOHYDRATE SUPPLY TO THE FETUS, possibility of MISCARRIAGE PROPERLY PRESCRIBED EXERCISE program outweigh the potential risks (coordination with woman´s obstetrician)

  24. Osteoporosis • Decreased bone mineral content - increased bone porosity - greater risk of fractures - increase 2 - 5x starting with onset of menopause • CONTRIBUTING FACTORS in postmenopausal women: Estrogen deficiency, inadequate calcium intake, inadequate physical activity.

  25. Eating Disorders a) Anorexia Nervosa • Females aged 12 - 21 are at greatest risk. • SYMPTOMS INTENSE FEAR OF FATNESS, DISTORTED BODY IMAGE, REFUSAL OF MEALS, AMENORRHEA Higher Risk Sports - appearance sports (figure skating, gymnastics, ballet), endurance sports (distance running), weight classification sports (horse racing)

  26. b) Bulimia Nervosa • Episodes of binge eating (large amount of food in a discrete period of time), feeling lack of control over eating, purging behavior (self-induced vomiting, laxative use, diuretic use) • Persistent overconcern with body shape and weight • PREVALENCE in female athletes estimated as high as 50  for elite athletes in certain sports • Female Triad - disordered eating, secondary amenorrhea, bone mineral disorders.

  27. Sex tests – feminity control • From 1968 to 2000 – women athletes undergoing genetic testing to prove their sex before they could compete.

  28. Buccal smear – XX chromosomes • Since 2000 replacement X chromosome testing with DNA-based methods to detect Y chromosomal material, principally SRY sex determining locus.

  29. Since 2000 sex tests abandoned • Gender verification has not been completely abandoned. Verification can be arranged, if athlete´s sex is called into question.

  30. Transsexual athletes • After puberty – male-female, female-male (1 in 12.000 men, 1 in 30.000 women). Criteria for competition (Olympic committee, 2004) 1)Surgical anatomical changes completed, including external genitalia and gonectomy 2)Legal recognition of their assigned sex confered by appropriate authorities 3)Hormonal therapy administered for sufficient length of time to minimize gender-related advantages in competitions

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