Lecture Nine

Adolescence -Characterised by: o Body systems reaching maturity (structurally and functionally) -Sexual maturity o The timing and tempo of changes is highly variable between individuals and gender Adulthood -Characterised by: o Attainment of full maturity o Peak performance and development

• Head x 2 • Arms x 4 • Trunk x 3 • Legs x 5

-Relative leg length and trunk length o Infants have smaller legs o Lower extremities grow faster than trunk during childhood and adolescence = ratio declines o Late adolescence the ratio increases again when trunk grows after leg growth has ceased o Females have generally shorter lower extremities than males

-Biiliocristal Breadth to Biacromial Breadth ratio -Breadth of hips compared to shoulders o Ratio higher in females indicating -Females hips make up a greater % of their shoulders -Males ratio declines as shoulder increase in size faster and greater than their hips

-Primarily by boys experiencing 2 years more of preadolescent growth than girls o Boys gain at ~5cm/year during females’ growth spurt = 10 cm of growth females don’t experience o Males have a higher peak o Testosterone increases Ca2+ deposition = bone growth -Mid growth spurt during childhood (6.5-8.5 years) o Not always apparent, more common in males. -Attainment of adult stature: o Growth can continue into mid 20’s o Annual increment of less than 1.0 cm o Four successive months increments of less than 0.5 cm

o Bone Matrix -35% organic -Collagen and Proteoglycans -Flexible strength -65% inorganic -Minerals = calcium and phosphate -Weight-bearing strength o Bone Cells -Osteoblasts -Bone forming cells -Produce organic material -Osteocytes -Osteoblasts surrounded by bone matrix -Osteoclasts -Bone-destroying cells -Reabsorption or break-down

o Zone of Resting -Chondrocytes do not divide o Zone of Proliferation o -Chondrocytes produce new cartilage o Zone of Hypertrophy -Chondrocytes produced in the Zone of Proliferation enlarge and mature o Zone of Calcification -Hypertrophied chondrocytes die, blood vessels from the diaphysis grow, osteoblasts deposit new bone matrix -Reach adult size when the Epiphyseal plate ossifies and becomes a line

• Articular cartilage at the end of the bone grows similarly to inside the bone • No clear-cut zones • Outer cartilage similar to zone of resting • Inner cartilage calcifies and ossifies • When it reaches full size bone stops replacing cartilage • This cartilage doesn’t become ossified unlike the epiphyseal plate

• Bone is deposited by osteoblasts on the outer surface - Bone is reabsorbed by osteoclasts on the inner surface

-Somatotyping is a system of classifying body types in terms of three categories: o Endomorphic (relative fatness) o Mesomorphic (relative musculoskeletal robustness) and o Ectomorphic (relative linearity or slenderness of a physique).

• The three numbers together give a somatotype number, with the Endomorphic score first, then Mesomorphic and finally Ectomorphic • The scores may also be plotted in a shield diagram or somatograph, representing the somatotype on a two-dimensional scale.

-An ectomorphic person would be: o Tall and thin o Narrow body o Thin arms and legs o Little body fat o Wiry muscles o In general, ectomorphs rank high on endurance, flexibility and agility -The calculation for the ectomorph rating is based on the measurements of: o Height o Weight o Height/weight ratio -Typical sports o Basketball o Long distance runners -Both examples have high ectomorph ratings but also relatively high mesomorphic ratings

-A mesomorphic person would be: o Strongly built o Broad muscular chest and shoulders o Very muscular arms and legs o Little body fat o In general, mesomorphs rank high on strength, endurance, power and agility -The calculation for the mesomorph rating is based on the measurements of: o Height o Breadths of the humerus and femur o Girths of the biceps (flexed and relaxed) and calf o The girths are corrected for body fat using the skinfold measure -Typical sports; o Gymnastics o Divers o Body builders o Weightlifters o Sprinters and Hurdlers o Jumpers o Pole Vault o Shot put & discus

-An endomorphic person characteristic includes; o Stocky o Large round body o Short thick neck o Short arms and legs o Tendency to store body fat o Sports people tend not to be in this category, being either more mesomorphic or ectomorphic o Still, it is possible that someone who is rated as an endomorph can modify their rating though diet and exercise to become more mesomorphic. -The calculation for the endomorphy rating is based only on; o The sum of 3 skinfolds (triceps, subscapular, supraspinale), corrected for height. o Therefore, the higher the skinfolds, the higher your endomorphy score -Not many sports require an endomorphic body type -Some individuals may not look like the typical athlete but are ‘sport fit’ for their particular sport

-Puberty = the period of time in which secondary sex characteristics develop and a child is transformed into a young adult

o Accelerated body growth o Rapid growth of the gonads o Increased production of gonadal hormones o External genital development in boys o Breast development and menarche in females o Pubic hair in both sexes = Attainment of the capacity to procreate

-The hypothalamic-pituitary-gonadal axis secretions throughout Infancy and Childhood are low o Possibly due to inhibition of neurons = low GnRH -During puberty there is a marked increase in production of sex steroids/hormones o GnRH = increase in LH and FSH

Ovaries secrete: • Estrogen (feminizing hormone) • Growth of ovaries and secondary sex characteristics • Stimulates GH = increase in height and pelvic widening • Stimulates fat deposition on the hips, thighs, buttocks and breasts • Supresses FSH and LH • Progesterone • Acts on the uterus to prepare for fertilization • Supresses FSH and LH • Inhibin – supresses FSH

-Thelarche = Breast Development o Formation of lobules and ducts by estrogen, progesterone and prolactin o Completion by glucocorticoids and GH o Adipose tissue and fibrous tissue enlarge the breast -Pubarche = Pubic and axillary hair growth o Stimulated by androgens from the ovaries and adrenal cortex -Menarche – 1st episode of menstrual bleeding o Occurs between age 11 and 16 o Less that 17% body fat can delay this event -Consider dancers and gymnasts

-Gamete = sex cells (sperm cell or oocyte) -The number of primary oocytes females are born with is the maximum they will ever have -From birth to puberty this amount reduces -Only 400 will mature to secondary follicles and be released -Birth to Puberty o Primary Oocyte -> Primordial follicle

• Growth of Granulosa cells = Primordial follicle -> Primary follicle • Cyclical hormonal changes = Primary follicle -> Secondary follicle • Secondary follicle continues to enlarge -> Mature follicle

-Ovulation = the secondary Oocyte is released -Fate o Pregnancy -Remaining granulosa cells  corpus luteum cells -Secretes progesterone and small amounts of estrogen -Remains active throughout pregnancy o No fertilization -Corpus Luteum remains active for 10-12 days then degenerates in to corpus albicans

-Typically, a 28-day cycle

-Follicular Phase o Development of follicles o Proliferation Phase -Of the Uterine mucosa -Luteal Phase o Existence of the corpus luteum o Secretory Phase -Maturation and secretion by uterine glands