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278 Cards in this Set
- Front
- Back
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What are hormones? |
• Produce by endocrine glands • Critical roles in growth and maturation • Endocrine, paracrine, autocrine, intracrine |
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What are hormone-like molecules? |
• Synthesized in other tissues / organs • Support growth and maturation |
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Mechanisms of hormonal actions |
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What are the classic endocrine glands? |
• Pituitary, thymus, pancreas, pineal body, parathyroid, ovaries, thyroid, adrenals, testes |
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What are the recent additions of endocrine glands? |
• Heart, kidneys, stomach, GI tract, liver, adipose, other tissues |
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What is the function of endocrine glands? |
• Regulate growth and maturation |
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Hormone pathway |
• Hormones act on tissues remote from origin - Released into circulation - All body tissue exposure • Reaches target tissue - Hormone receptor (cell wall / cytoplasm / nucleus) - Sensitivity |
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The chemical structure of endocrine hormones are heterogenous, what 3 derivatives form them? |
• Protein (derivative) • Cholesterol derivative = Steroid • Amine derivative (amino acid) |
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What organs do the protein derivative of endocrine cells come from and what are their functions? |
• Pituitary, pancreas, parathyroid • Interact with cell surface receptor |
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What organs do the cholesterol derivative of endocrine cells come from and what are their functions? |
• Testes, ovaries, adrenal cortex
• Cytoplasm receptors • Hormone-receptor complex - Nuclear translocation • Nuclear receptor - Mediated gene expression |
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What organs do the amine derivative of endocrine cells come from and what are their functions? |
• Adrenal medulla, thyroid • Cell surface / nuclear receptors |
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Hormone action illustration of protein, cholesterol and amine |
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Human genes for endocrine hormones cloned. Which two encoded hormones are produced commercially? |
• Insulin • Growth hormone |
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Features of hormone receptors? |
• Hormone specific • Concentration (number) varies across cells |
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When do hormone receptors increase (up-regulate) and decrease (down-regulate)? |
• May increase (up-regulate) during growth / puberty and decrease (down-regulate) with aging |
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How are hormone receptors influenced? |
• Influenced by circulating hormones - Sustained / elevated hormone concentration leads to receptor development (testosterone –beard) - Down regulation causes resistance |
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What are the 3 process modulators for hormone actions? |
• Circulating hormone concentration • Receptor affinity • Target cell responsiveness |
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What is the action of hormones? |
• Causes a physiological response • Allows for variation in growth / maturation |
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What are the 3 hormone regulatory actions? |
• Morphogenesis • Integration • Maintenance |
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What does morphogenesis regulate? |
• Regulation of physical growth / maturation - Growth-promoting hormones • Required for full expression of intrinsic growth |
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What does intergration regulate? |
• Circulating integration of 'whole body response' to internal/external stimuli • Adaptive reaction to stress |
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What does maintenance regulate? |
• Maintain internal environment - Calcium, salt, fluid balance, blood glucose level |
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Positive vs. Negative feedback |
• Positive feedback - Widening the gap - Self-reinforcing • Negative feedback - Narrowing the gap - Self-correcting |
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What happens in the real world with regards to positive/negative feedback? |
• Incentive to increase performance • Narrows the gap if performance poor • Increases the gap if attempting to enhance performance |
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What are the two functions of the pancreas? |
• The pancreas has two functions: - To make hormones (endocrine) - To produce enzymes for digestion (exocrine) |
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Individual beta cells make up the Islets of Langerhans. What two hormones do these Islets produce? |
• Insulin • Glucagon |
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What is the main function of negative feedback? |
• Main homeostasis - Blood pressure maintenance - Temperature regulation - Blood glucose regulation |
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What is the negative feedback response if a level is too high? Too low? |
• If a level is too high the response is to reduce level • If a level is too low the response is to increase level |
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Blood glucose regulation illustration |
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Main function of positive feedback? |
• Ability to maintain/accelerate stimulus direction |
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3 examples of positive feedback maintaining/accelerating stimulus direction |
• Nerve action potential - Na+ leakage - Open channels - Explosion of leakage along axon • Injury - Blood coagulation (clotting) - Clotting factor activation sequence to produce blood clot • Uterine contraction during childbirth - Oxytocin |
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What is the other function of positive feedback? |
• 'Counter' signal to suppress/break the loop |
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Illustration of uterine contraction during childbirth |
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What are growth-promoting factors? |
• Highly potent molecules - Involved in complex cascades of molecular events • Secreted - One or a few types of cells / many tissues - Systemic / highly localized effects • Potentiated by other growth-promoting factors |
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What are growth-promoting factors involved in? |
• Growth/maturation • Recovery from injury, burn, surgery, cancer • Therapeutic models |
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What are some examples of growth factors and their corresponding functions? |
• Fibroblast growth factor - Angiogenesis, wound, embryonic develop • Epidermal growth factor - Cell growth, proliferation, differentiation • Nerve growth factor - Neuron growth, maintenance, survival • Platelet-derived growth factor - Angiogenesis, cell growth/division • Transforming growth factor - Tissue regeneration / proliferation • Osteoclast growth factor - Bone maintenance / remodelling • Vascular endothelial growth factor - New vessels embyonic / injury / exercise / collateral circulation • Tumor necrosis factor - Cell death / cachexia (wt loss/fever) • Insulin like growth factors - IGF-I -growth, IG-II fetal growth |
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What is the function of hypothalamic releasing / inhibiting hormones? |
• Modulates release of anterior pituitary hormones |
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Flow chart from hypothalamus to anterior pituitary venous plexus |
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What are the hypothalamic releasing/inhibiting hormones as well as their corresponding function? |
• Growth hormone-releasing hormone (GHRH) • Somatotropin-releasing-inhibiting factor (SRIF) - Inhibits GH and TSH release • Thyrotropin-releasing hormone (TRH) - TSH release • Corticotropin-releasing hormone - ACTH release • Gonadotropin-releasing hormones - Leuteinizing hormone-releasing hormone (LHRF) - Follicle stimulating hormone-releasing hormone (FSHRH) |
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Relation of hypothalamus to pituitary illustration |
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List of hormones and their corresponding location |
• Growth hormone (somatotropin) - General growth due to inhibition of somatostatin • Coricotropin (adrenocorticotropic hormone) - Adrenal cortex • Thyrotropin - Thyroid gland • Gonadoropins (FSH/LH) - Ovaries/testes • Prolactin - Gland inactive/ineffective in absence of tropic hormones |
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What are tropic hormones essential for? |
• Target gland hormone release |
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Schematic relations between hypothalamus, anterior pituitary, and other endocrine glands |
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Growth hormone/growth factor illustration |
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Specific tissue targets are influenced by what? What are these mediated by? |
• Direct influence by GH - Mediated by insulin like growth factors |
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What is IGF-I? |
• Linear growth regulation • Primary production in liver • Stimulated by levels of GH (+ relationship) |
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What is the function of IGF-II? |
• Fetal growth
- Muscle differentiation / organogenesis |
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What is the main function of IGF-I? |
• Growth promoting effects
- Distant to release - Protein synthesis / cell proliferation (mitogen) - Nitrogen retention / cell division / anabolism |
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Where is IGF-I most active? |
• Most active in cartilage (long bones) - Growth plate cartilage cell proliferation - No acceleration in skeletal maturation or fusion |
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What is the paracrine hormone function? |
• The hormone synthesized in and released from endocrine cells binds to its receptors in nearby cells and affects their function |
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What is autocrine hormone function? |
• Hormone binds to receptors on and affects the function of the same cell that produced it |
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Interaction between growth hormone and IGF-I function |
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Is anterior pituitary content related to GH level? |
• No |
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How is growth hormone released? |
• Release is pulsatile (number + amplitude) throughout the day - Largest at sleep onset |
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How is concentration of growth hormone effected with growth and maturation? |
• Children have more 'pulses' / 24 hours - Higher level than adults • Concentration increase in childhood - Peak level at PHV - Highest magnitude of pulses (nocturnal) • Concentration decline into adulthood - Magnitude declines to preadolescent level |
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Blood levels of growth hormone in boys illustration |
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Growth hormone and puberty in boys illustration |
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What are some other factors influencing GH level? |
• Physical activity • Nutritional status • Psychological stress • Social stress |
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GH - IGF-I relationship illustration |
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What are 4 types of thyroid hormones? |
• Thyrotropin-releasing hormone (TRH) - Hypothalamus • Thyroid stimulating hormone (thyrotropin) - Anterior pituitary • Thyroid hormone = thyroxine (T4) - Thyroid gland • Triidothyronine (T3) - Thyroxine conversion in peripheral tissue |
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What are the similarities/differences between T3/T4? |
• Same metabolic effect • T3 more rapid effect - More potent |
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What are the two main actions of thyroid hormones? |
• Influence growth and maturation • Calorigenic |
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How do thyroid hormones influence growth and maturation? |
• Skeletal growth / maturation, muscle development, sexual maturation, mental development • Acceleration of biological processes • Throxine essential for optimal effect of GH |
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How are thyroid hormones calorigenic? |
• Stimulate oxygen uptake / energy expenditure • Increased mitochondrial oxidative metabolism - Skeletal muscle, liver, kidneys |
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Why is chronic autoimmune hypothyroidism / congential rare in Western world? |
• Due to iodine additives - 1:3000-4000 births |
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What does hypothyroidism result in? |
• Growth failure - Reduced rate of growth - Linear bone growth impaired (infantile proportions) - Delayed skeletal / sexual maturation - Muscular development impaired |
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What occurs with severe / persistent hypothyroidism early? |
• Irreversible stunted physical growth, mental retardation • Early detection / treatment can allow normal growth / development |
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What happens if there is an excess of hyperthyroid? |
• Excessive growth initially • Weight loss - Increased metabolic demand without increased energy intake |
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Where is calcitonin secreted and what is its function? |
• Secreted by thyroid during high circulating calcium • Inhibit bone resorption / increase deposition in bone |
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What is the function of parathyroid hormone? |
• Stimulates an increase in circulating calcium • Vital for normal bone / dental growth and maturation • Increases osteoclastic activity (bone resorption) • Reduces renal clearance of calcium (kidney) |
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What is the combined function of calcitonin and parathyroid hormone? |
• Maintenance of calcium level within narrow limits |
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What are the adrenal glands innervated by? |
• SNS |
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What is the function of noradrenaline? |
• Stimulates release of adrenaline (epinephrine) |
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What is the agonist to noradrenaline? |
• Catecholamine - Stimulatory / inhibitory effects |
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What is the function of adrenal hormones? |
• Influence force / contraction rate of cardiac muscle, blood pressure (systolic/diastolic), GI motility, bronchodilation, insulin secretion, adipose tissue lipolysis, glucose and fatty acid metabolism, thermogenesis, adequate regulation of production / degradation, indirect effect on normal growth / maturation |
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What are the 3 types of catecholamines? |
• Adrenaline / epinephrine (H+NT) • Norepinephrine / noadrenaline (H+NT) • Dopamin (NT) |
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What is the function of adrenaline / epinephrine? |
• Metabolic / brochodilator effects on organs without direct SNS innervation |
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What is the function of norepinephrine / noadrenaline? |
• SNS neurotransmitter • Increase vascular tone - ↑ heart contraction |
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What is the function of dopamine? |
• Brain reward-motivated behaviour • Motor control • Hormone release • Inhibits norepinephrine release • Vasodilator • ↑ Na release • ↓ insulin |
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What kind of hormones do the adrenal cortex produce? |
• Production / release of steroid hormones - Direct growth effects |
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What are the 6 common steroids produced in the adrenal cortex? |
• Mineralocorticoids - Aldosterone • ACTH • Glucocorticoids - Cortisol • Adrenal adrogens - Hydroepiandrosterone - estrogens • Testosterone & progesterone - Small amounts |
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HPA axis illustration |
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What is the function of ACTH? |
• Regulation of adrenal hormones • Primarily cortisol (glucocorticoid) - In response to stress, including severe stress like infection & hemorrhage |
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What is the function of the mineralocorticoid aldosterone? |
• Produced in the kidney • Blood pressure ↑ leading to water retention • Na+, K+ homeostasis |
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What is the function of the glucocorticoid cortisol? |
• Responds to stress • ↑ blood sugar & metabolism (fat, protein, carbs) • ↓ immunity • ↑ secretion with growth (proportional to body size) |
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What is the function of adrenal adrogens? |
• Biosynthesis of androgen / estrogen steroids • Similar to production by testes • Development of masculine characteristics / nitrogen retention • Male androgens produced - Adrenal and testes • Low and less biologically significant - Adrenal • Adrenal androgens required for complete sexual / reproductive maturity • Female androgens only produced in adrenal cortex |
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What are the two problems associated with abnormal adrenal hormone levels? |
• Pheochromocytosis • Excess cortisol |
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What is pheochromocytosis? |
• Catecholamine-producing tumors (medulla) • Headache, ↑ HR/BP/blood sugar, weight loss • Orthostatic hypotension (SBP ↓ 20/ DBP ↓ 10 mmHg) |
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What happens with excess cortisol? |
• Treatment with cortisol, prednisone, dexamethasoneleads to allergy, asthma, autoimmune diseases • Increased protein catabolism in bone (elsewhere) • ↓ proliferation of cartilage in growth plates • Stunted growth |
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What are the gonadal glands? |
• Secrete gonadal hormones • Testes and ovaries • Hormone-secreting and gamete-producing • Males: testosterone (cells of Leydig) • Females –ovarian follicles (estrogens/progesterone) - Vary with menstrual cycle phase |
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Mass of ovaries through development |
• Gradual ↑ during childhood • Slight ↑ adolescence |
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Mass of testes through development |
• Little mass ↑ during childhood • Dramatic mass ↑ at puberty |
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Where are gonadotropic hormones produced? |
• Anterior pituitary |
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What are the two gonadal hormones? |
• Follicle stimulating hormone (FSH) • Leutinizing hormone (LH) |
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what is follicle stimulating hormone (FSH) function in males and females |
• Females - Ovarian follicle growth (not maturation) - Estrogen secretion • Males - Seminiferous tubule growth - Stimulates production of sperm |
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What is luteinizing hormones function in females and males? |
• Females - Ovarian follicle maturation - Ovulation, corpus luteum development (menstrual) - Stimulates etsrogen production by ovaries • Males - Interstitial cells of Leydig to produce testosterone |
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When does FSH and LH production occur in males and females? |
• Females - Cyclical in late puberty • Males - At sexual maturity becomes constant |
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Gonadal releasing hormones Luteinizing releasing hormone and follicle stimulating hormone releasing hormone do what? |
• Stimulates LH/FSH release - ↑ testosterone/estrogen through negative feedback - Form activin / inhibin in testes / ovaries |
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What is activin? |
• Allows androgen synthesis • Enhance LH action • Follicle maturation/testosterone |
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What is inhibin? |
• Inhibits FSH being produced in anterior pituitary • ↓ follicle (grow) sperm production |
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What happens to FSH levels throughout maturity? |
• Higher in infant girls • Childhood - Females 2X males • Puberty - Females ↑3X (B4 PH4) - Males ↑6X (G5 PH5) • Adulthood - Remain high both genders - Menopause dramatic ↑(10X) |
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What happens to LH levels throughout maturity? |
• Variable to age 1 • Similar gender level to puberty • At B2/G2 / PH2 - Females ↑ 10X - Males ↑ 20X • Early adulthood - Females / males ↑ to similar level |
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What are the two sex steroids and where are they synthesized? |
• Testosterone • Estradiol • Synthesized in testes, ovaries, adrenal cortex and conversion of steroid precursors (adipose) |
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What is testosterone? |
• Major / most abundant male androgen •Cholesterol percursors (testes / adrenal cortex) • Testosterone converted to dihydrotestosterone (peripheral tissue) - Greater adrogenic activity (3X) - Maturation of male secondary sex characteristics • Testosterone converted to estradiol - Prevents apoptosis of sperm cells |
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What is apoptosis? |
• Process of programmed cell death without damage (50-70 billion cells / day) |
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What is estradiol? |
• Most produced in ovaries - Small amount form adrenal cortex precursors • ‘Growth hormone’ of female reproductive organs • Stimulation of female secondary sex characteristics • Epiphyseal plate ‘closure’ - Lack of estradiol may result in delayed plate closure - Very tall / osteoporosis (early) • Women’s mental health - Fluctuation / low levels associated with low mood |
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What happens to levels of testosterone through maturity? |
• Boys > girls infancy • Childhood - No gender difference • Steady increase adolescence |
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What happens to levels of estradiol through maturity? |
• Pre-adolescence - No gender difference • Dramatic increase at sexual maturity |
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What is the effect of androgens? |
• Growth and maturation of male primary and secondary sex characteristics • Thickening of laryngeal cartilage - Voice change • Nitrogen retention (anabolic effect > males) - Females -adrenal androgens • Bone growth - Longitudinal - + GH / IGF-1 bone breadth (stimulates GH / IGF-1 axis) • Skeletal maturation - Aromatization of androgens to estrogens (aromatase) |
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What is the effect of estrogens? |
• Growth and maturation of female primary and secondary sex characteristics • Gynoid profile of adipose tissue distribution - Hips, buttocks, breasts, medial calf • Nitrogen retention • Bone growth - ↑bone matrix, positive calcium balance • Accelerate skeletal maturation - Initiate / complete epiphysea lclosure - Primary determinant of final stature |
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What is the preadolescent 'fat' wave? |
• Increase in adrenal steroid - Dyhydroepiandrosterone • Fat accumulation - Age 7 to 12 both genders |
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What counters the 'fat' wave in adolescent males? |
• Testosterone + GH - Fat mobilizing (male fat loss) |
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What is meant by insulin and glucagon being mutually antagonistic hormones? |
• Control glucose homeostasis - Insulin ↓ blood sugar - Glucagon ↑ blood sugar |
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What is insulin? |
• Stimulates uptake of glucose - Adipose / muscle tissue (remember GH stimulates lipolysis) • High blood glucose + glycogen stores - Glucose to fatty acids • Inhibits hepatic glucose production / adipose lipolysis • Essential for full expression of GH/IGF-1/IGF-2 on protein synthesis for growth • Mitogenic factor - Cellular hyperplasia / hypertrophy |
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What percent of the pancreas is endocrine and what percent is exocrine? |
• 2% endocrine • 98% exocrine |
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What are the endocrine hormones and their functions? |
• β cells - Insulin • α cells - Glucagon • δ cells - Somatostatin (GHIH) - Inhibits insulin/glucagon (paracrine) • PP cells - Pancreatic polypeptide - Self regulation (endocrine / exocrine) |
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What is produce as exocrine hormones? |
• Digestive enzymes |
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What is the function of glucagon? |
• Mobilization of glycogen breakdown - Hepatic glycogenolysis • Triglyceride breakdown/lipolysis - Increased fatty acids |
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How and when is leptin produced? |
• Discovered 1994 • Produced by adipocytes (30 pulses) • Secreted in proportion to subcutaneous fat mass (variable) - Some produce < / > expected • Increase in cord blood - 34 weeks gestation • Males - ↑ puberty - 3 years later = prepubertal level • Females - ↑ puberty - Increase through puberty • Females > Males |
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What is leptin? |
• Important regulator in long term food consumption - No increase in leptin with single meal • Reduction in food intake - Anatgonizes action of orexigenic agents (↑appetite) - Interaction with hypothalamic neuropeptide Y decrease appetite - Potentiates action of anorexigenic agents (↓appetite) • Increase metabolic rate ? • ↑glucose / lipid metabolism |
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What happens in the absence of leptin? |
• Severe obesity • Increased food intake • Hypogonadotropic hypoggonadism • Onset of puberty delayed / infertility |
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What happens with a leptin deficiency? |
• Growth retardation • Hypothyroidism • High ACTH/cortisol due to leptin not regulating HPA axis - ↑ glucocorticoid - ↑ risk type 2 diabetes |
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What are the protective effects of leptin while undernourished? |
• ↑ appetite • ↓ adiposity - ↓ leptin production / release • ↓ metabolic rate - Protect fat stores |
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Leptin biology illustration |
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Leptin and the onset of puberty illustration |
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What is puberty? |
• Transition period between juvenile and adult state |
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Puberty flow chart |
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Regulation of puberty during development |
• Early infancy through childhood - Inhibition of GnRH (gonadotropin releasing hormone) • Late childhood / prepuberty - Reduced inhibition GnRH • Increased output (ant Pituitary) - LH and FSH • Gonadal maturation • First sign of sexual maturation - Increased LH secretion during sleep - Pulses extend to daytime • At sexual maturity - LH secretion day and night equally in males - LH secretion develops a cyclical pattern in females |
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What is the key hormonal event during the menstrual cycle and when does it occur? |
• Gonadotropin surge - 1-2 days prior to onset of 28 day cycle |
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What happens during the menstrual cycle? |
• GnRH pulses signal LH/FSH pulses - Production of ovarian hormones |
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When does the first menstrual cycle usually occur? |
• At menarche - Late pubertal stage (B4/PH4) |
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The menstrual cycle is broken down into what two 14 day cycles? |
• Follicular phase • Luteal phase |
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What happens during the follicular phase? |
• Menstruation - 3 to 7 days (endometrium destruction) • Estrogen (estradiol) levels reach low point - ↑GnRH / LH / FSH • ↑FSH triggers maturation of ovarian follicle • ↑LH midcycle peak - Follicle (mature) releases egg in fallopian tube - Ovulation (14 days) - FSH peak (lower) • Peaks are just prior to ovulation - LH and FSH rapid decline |
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What happens during luteal phase? |
• Progressively slower release of LH - Increasing level progesterone • No fertilized egg - ↑estradiol - Negative feedback (hypothalamus) - Slows LH / FSH • Post-ovulatory phase - Reconstruction endometrium (begins after menstruation) - ↓progesterone / estradiol • Cycle continue in the absence of fertilization |
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Normal menstrual cycle illustration |
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What happens during early menstrual cycles? |
• Anovulatory - No mature egg • First cycle is the longest - Length/variation ↓ after first 3 cycles |
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Summary of hormones involved in the regulation of growth and maturation |
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What 4 variables are looked at for energy expenditure and physical activity? |
• Assessment • Developmental trends • Levels of physical activity - Growth/maturation-related changes • Factors influencing physical activity |
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Why do we look at energy expenditure/physical activity? |
• Major modifiable risk factor for chronic disease |
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What is physical activity? |
• Any bodily movement produced by skeletal muscle that results in energy expenditure - Important biological implications |
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• What are the 3 components of physical activity? |
• Mechanical - Force / velocity/ acceleration • Physiological - O2 uptake / metabolic energy / METs • Behavioural - Type / environmental and social influence |
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The sum of what 3 expenditures make up total body energy expenditure (TEE)? |
• Resting energy expenditure (BMR) • Diet-induced energy expenditure • Activity/exercise-induced energy expenditure • TEE = REE + DEE + EEE |
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What is adaptive energy expenditure? |
• Energy expenditure due to climatic stress - Exposure to heat / cold |
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When/where is resting energy expenditure measured? |
• Measured morning (rested) / fasted - Supine / calm setting (distraction) - Thermoneutral environment (23-25 C / 50% RH) |
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How is resting energy expenditure measured? |
• VO2 measurement (20 minutes stable) - Mouthpiece - Mask - Ventilated hood (canopy) - Respiration chamber (long term) |
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What is basal metabolic rate (BMR)? |
• Energy released/consumed sufficient for vital organ function |
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What is the energy expenditure breakdown for various body parts? |
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What is the variability between individual BMRs? |
• Top 5% BMR > low 5% by 30% |
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What is the average (estimated) BMR? |
• 1500 kcal/day - Range 1275 to 1725 kcal/day |
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What 3 variables affect BMR? |
• Height • Age • Weight |
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What is the BMR equation for men/women? |
• Men BMR = 66.4730 + (13.7516 x weight in kg) + (5.0033 x height in cm) –(6.7550 x age in years) • Women BMR = 655.0955 + (9.5634 x weight in kg) + (1.8496 x height in cm) –(4.6756 x age in years) |
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How is BMR adjusted for physical activity? |
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BMR ___________ with age / loss of mean mass |
• Decreases |
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What is diet-induced energy expenditure? |
• Energy required for mechanical and chemical processing, absorption, storage - Increase REE by 10-15% |
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When does diet-induced energy expenditure increase BMR? |
• 3-4 hours postprandial - Proteins > carbs > lipids |
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What is the most variable component of TEE? |
• Exercise energy expenditure - Short term increase = 10 to 20x REE - In 24 hours may be 50% TEE |
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What is a MET? |
• Metabolic equivalent of a task |
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What does an MET tell us? |
• Energy cost of performing a given task |
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What is the average/adult MET? |
• 3.5 mlO2/kg/min • 1 kcal/kg/hour |
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EEE & RMR are higher for which age group? |
• Children |
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How do we measure the 24 hour activity related energy expenditure? |
• TEE/REE = physical activity factor - 1.0 = no activity - 2.5 to 4.5 = extreme activity - average = 1.7 to 2.0 - Lowest in sedentary |
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Why is the original MET chart not well adapted for children? |
• Chart is based on average / stead state activity whereas the typical activity pattern of children is "burst" not steady state |
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What is the better MET chart? |
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What does 1 Kj = ? |
• 0.23 kcal |
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When assessing physical activity you can induce changes, what is the term used for this? |
• Reactivity - Need to control/minimize |
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Assessment tools chart (1 of 2) |
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Assessment tools chart (2 of 2) |
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What do accelerometers do? |
• Register acceleration within movement - Initially single plane, now 3 planes • Validated against direct observation, heart rate, respiration chamber, doubly labeled water - r = 0.5 to 0.9 • Data = counts per period - Then converted to kcal |
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What does the FitBit force (accelerometer) measure? |
• Steps, calories, stairs, daily activity, sleep (quantity/quality) |
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What will an accelerometer show more of in active vs sedentary boys? |
• Vector counts |
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What is a heart rate monitor? |
• Continuous Heart Rate - Most popular method for estimating energy expenditure over time (24 to 72 hours) - Socially acceptable, minimal reactivity • Individually ‘calibrated’ with VO2 - Excellent indicator of metabolic aerobic energy expense • Calibration - VO2 measured supine, standing , at least four intensities - Regression line of HR -VO2 |
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What factors influence heart rate other than metabolic rate? |
• Climatic conditions • Body temp • Aerobic fitness • Resting HR • Muscle mass / activity • Hydration • Emotional state • Last meal timing |
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Multiplying HR values by individual regression equation typically does what? |
• Overestimates energy expenditure |
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How do we overcome this overestimation? |
• Use HR only to estimate time in mild/mod/vig PA then subtract resting (basal HR) • Only calculate EEE |
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What is doubly labelled water? |
• Use of stable, heavy, non-radioactive isotopes - 2H (deuterium / D) + 18O (oxygen-18) = D218O • Gold standard for measurement of EE - Least reactive |
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How does doubly labelled water measure EE? |
• Drink measured sample - Diluted in total body water in 4-8 hours • Measure clearance of isotopes over time - Up to 14 days in body fluid –urine / saliva - 18O present in H2O and CO2 - 2H only present in H2O - Difference between 18O and 2H = CO2 elimination - CO2 proportional to O2 consumption (TEE) - Depends on RQ (fat 0.7, protein (mixed) 0.8, carbohydrate 1.0) |
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What is the developmental trend of physical activity in children 3 to 10 years of age? |
• Spontaneous, non-organized, intermittent activity • Short bouts - Most not < 3 seconds but 95% < 15 seconds |
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What is the developmental trend of physical activity in older adults? |
• More organized, more regular, prolonged duration after school • Organized sport = 20% of boys / 16% of girls TEE |
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Reported recreational physical activity among Canadian adolescents 10 to 19 years of age |
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What is the age/gender related decline in activity? |
• Second decade of life (as early as 6 years) - 24-hour energy expenditure ↓ - Physical activity ↓ spontaneous • EE ↑ with growth (↑ lean tissue) - Growth ↑ > RMR ↑ - EE per kg ↓ with age • Girls earlier and more rapid decline - 9th grade: girls 60% of boys - 12th grade: girls 40 % of boys |
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Age/gender-related decline in activity graph |
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What is the trend in physical education class participation? |
• 1985: 1st through 6th grade = 97% • 1985: 11th / 12th grade = 49% - 1991 = 42% - 1995 = 26% |
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Does physical activity track from childhood → adolescence → adulthood? |
• Low to moderate correlations during childhood/adolescence using recall method |
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How can we change the pattern seen in physical activity (decline)? |
• Encourage motor skill proficiency in childhood • Choice of participation in youth • Make it easy for them to participate |
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What are the 4 factors associated with physical activity and energy expenditure? |
• Biological • Psychological • Social • Physical enviroment |
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Factors associated with physical activity and energy expenditure chart |
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What is the main thing required to increase physical activity? |
• Opportunity |
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What is the historical perspective on physical activity? |
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What is habitual activity? |
• Estimated lifestyle activity - Light / moderate / vigorous levels - Hours per day or week - Estimated using interviews, questionnaires etc |
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What is important when measuring habitual activity? |
• Qualification / quantification if important - Mild / moderate / vigorous - Active vs inactive - Not enough information |
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What are the 3 types of studies that influence physical activity? |
• Correlational • Comparison • Experiment |
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What do correlational studies look at? |
• Relationship between habitual physical activity and growth/maturation/performance |
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What do comparison studies look at? |
• Active vs. inactive children - Growth characteristics - Environmental factors –school system (PA / PE athletes vs. non-athletes • Assumes ‘regular’ training - Differences attributed to training ? - Inherent differences –size, maturity status,.. |
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What is the definition of active? |
• Engaging or ready to engage in physically energetic pursuits. |
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What do experimental studies look at? |
• Comparison of individuals exposed to ‘intervention’ vs. no exposure - Intra-study differences in ‘stimulus’ - Type, intensity, duration, status at enrollment - Subject selection, motivation, environmental control - Intervention duration –growth / maturation - Most studies –short term (8-20 weeks) |
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What is sports specific training |
• Seasonal over years |
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What do unilateral sports such as racquet sports all the individual to control? |
• Control dominant arm vs. non- dominant - Effect of activity on skeletal, muscle, adipose tissues |
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What do regular physical activity do to stature? |
• No impact on stature/growth rate - Does not stunt growth |
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What do active boys (>6 hours/week) see in terms of stature? |
• Taller |
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How does activity effect body weight? |
• Sedentary boys > weight post adolescence |
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How does activity effect body composition? |
• Active (>6 hours week) were: - Taller - Advanced skeletal maturity - Earlier PHV - % body fat decreases |
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What are the 3 types of specific tissue? |
• Skeletal tissue - Framework = bone • Skeletal muscle - Major work-producing, oxygen consuming • Adipose tissue - Energy storage |
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What is muscular contraction / weight bearings effect on skeletal tissue? |
• Tensile + compressive forces • Mechanical strain of weight bearing / activity stimulate bone formation • Intermittent growth plate compression stimulate bone growth |
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Highest habitual activity had what effect on skeletal tissue? |
• Greater PV of bone mineral accural • Greater accumulation during growth spurt • After PHV had greater total-body bone mineral - Active boys = 9% - Active girls = 17% |
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What is the main benefit of PA on skeletal tissue? |
• Bone mineral content from childhood/adolescence → adult - Females most important |
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What effect does PA have on bone growth (length)? |
• Habitual PA no influence • Weight bearing + PA essential |
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Excess pressure may inhibit linear growth as seen in what disease? |
• Osgoode-Schlatters - Inflammation of the patellar ligament at the tibial tuberosity. It is characterized by a painful lump just below the knee and is most often seen in young adolescents |
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What occurs during postnatal muscle growth with activity? |
• Constant fibre number (hyperplasia) • ↑ in muscle fiber size (hypertrophy), contractile protein, enzyme concentration |
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What is the effect of progressive resistance training on skeletal muscle? |
• ↑ muscle size in muscle composed of type II (fast twitch) |
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What is the effect of endurance training on skeletal muscle? |
• ↑ relative area type I • ↑ enzyme activity (oxidative) |
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What occurs to skeletal muscle with prepuberty resistance training? |
• ↑ strength in the absence of hypertrophy (minimal) • Pubertal males ↑ with hypertrophy |
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What is the training effect of fiber type distribution? |
• No effect? |
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What is the training effect on fiber surface area? |
• Resistance training - No effect • Endurance training - ↑ in type I and type II |
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What is the training effect on metabolic capacity? |
• Sprint training - ↑ phosphofructokinase • Endurance training - ↑ succinate dehydrogenase *6 months post-training, metabolic capacity returns to pre-training levels with no training* |
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Schematic of fat cell size/number during growth |
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What was the effects of a 4 months physical activity program on obese children 7-11 years old? |
• ↓ abdominal subcutaneous • No change in abdominal visceral |
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What is the effect of PA on adipose tissue in male adolescents? |
• Association between time spent in vigorous activity and reduction in subcutaneous trunk fat |
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What is the effects of a 15-20 weeks intensive aerobic training regiment on young adult males/females? |
• Males - ↓ trunk > ↓ extremities • Females - ↓ trunk = ↓ extremities |
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Overall effect of PA on adipose tissue |
• Reduction in cell size not cell number • Training may ↑ lipolysis (mobilization + oxidation) |
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What is PA effect on biological maturity? |
• Skeletal Maturity - Habitual physical activity → bone mineral accrual - No influence on skeletal maturity • Somatic Maturity - Habitual physical activity no effect on age at PHV or magnitude of PHV (boys) • Sexual Maturity (females) - Habitual physical activity has no effect on age at menarche |
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The assumption is that habitual activity → more fit, does this hold true? |
• Low correlations - Endurance → physical activity / age / gender - Physical activity has 3 to 25% variation |
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When comparing inactive and active adolescents, more active have what attributes? |
• Higher cardio respiratory fitness only - Similar performance on other fitness variables such as static arm, sit and reach, vertical jump etc. |
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What 3 variables make up for the low correlations between habitual activity and fitness? |
• Field tests of fitness are unreliable / not valid • Habitual activity in children rarely reach high aerobic level for sustained time • Fitness changes occur due to growth and maturation independent of PA |
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What influence does time of maturation have on fitness scores? |
• Late maturing male has low fitness score (strength) - Smaller and lower muscle mass • Early maturing male has high fitness score - Taller, heavier, higher muscle mass • Early maturing female has lower score - Higher % body fat |
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The responsiveness of children/adolescents to a training stimulus is influenced by what? |
• Age, gender, growth / maturity statusprior experience (opportunity), pre-instruction / pre-training level of skill, strength, aerobic / anaerobic power, genotype, genotype-environment interaction |
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What is trainability? |
• Responsiveness of developing individuals to the training stimulus at different stages of growth and maturation |
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At what age are fundamental movement patterns well established? |
• 6-8 years of age |
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What happens to motor skills with instruction/practice? |
• Refine existing motor pattern • Learn new skills |
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What are sports skills? |
• Modifications / combinations of fundamental patterns |
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Early opportunity with motor skills is beneficial when? |
• Middle childhood |
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What may be the key to trainability of motor skills? |
• Genotype - Ease of improving / learning skills with practice |
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Why was training for muscular strength not historically recommended prepuberty? |
• Insufficient testosterone levels • Potential premature epiphyseal closure/damage |
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What effect does training have on muscular strength? |
• Some increase due to learning effect / growth • Minimal hypertrophy • Neural adaptation - ↑ motor unit recruitment / firing frequency changes in intrinsic contractile characteristics |
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Yes resistance training useful for children/adolescents? |
• Yes it is safe and effective • ↑ strength with adequate supervision / technique |
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How does strength training transfer to performance? |
• Some change in vertical jump / sit and reach - Variability explained by growth |
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How does strength training transfer to endurance? |
• No data in children/adolescents • In adults: - Replacing 1/3 aerobic training volume with explosive strength training improves 5km performance time - Improved running economy / anaerobic capacity |
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How well do strength gains persist? |
• Strength gains revert to pre-training levels - Several weeks post training cessation • Unsure how much training is required to maintain • Genetic influence - Response to strength training is independent of genotype |
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How do we assess anaerobic power? |
• Vertical jump, 40 yd dash, treadmill time to exhaustion (11km/h 18%), 30-second cycle (Wingate test) |
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What is the effect of 9 weeks of high intensity training on anaerobic power in 10-11 year olds? |
• ↑ peak power (10%) • ↑ mean power (14%) |
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How is the relationship between field performance and anaerobic power measurement? |
• Moderately strong |
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What does short-burst sport activity training lead to? |
• ↑ anaerobic power - No change in 40 yd dash time - Changes may occur in the ability to resist fatigue during short-term high intensity sprints |
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What variable of blood lactate is used to assess anaerobic power? |
• Anaerobic threshold (AT)(VT)(LT) - When lactate begins to accumulate |
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There is a moderate relationship between AT and endurance, what effect does run, interval and cycle training have on VT? |
• Increases in VT 13-19% |
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What is the change in relative VO2 max (ml/kg/min) with training? |
• Little trainability in those younger than 10 years - VO2 ↑ 2 ml/kg/min (5%) |
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What is the mean change in VO2 max with training? (Aerobic power) |
• Increase 6.5% - Range is -2.4% to 19.7% - Evidence for large individual variance |
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What is the transfer of aerobic training to performance? |
• Endurance performance (1-mile run, 12-min dist) improves with age regardless of training • elative VO2max remains stable • Running economy improves with age - ↓ cost of locomotion |
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Trainability of aerobic power on age? |
• Limited trainability under 10 years of age • Is trainable in older children, adolescence - Individual variability |
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What is the pesistance of gains in aerobic power/capacity? |
• Some suggest return to pre-training level • Genetic contribution - Less variation between MZ twin than DZ |
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Effect of the specificity of training and effect of detraining findings from study of combined training? |
• Two experimental groups increased performance • Control group increased performance < training groups • Year 2 (no training) experimental groups performance decreased endurance not strength • Year 3 training resulted in greater improvements • Endurance focus group had better endurance performance • Speed focused group had better speed performance • Both groups had similar performance in 300-and 1,000 m runs |
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Peak VO2 relative to peak height velocity in boys of contrasting activity status |
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Youth sport participation from 1992 to 2005 chart |
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What are the 3 influences of intensive training? |
• Growth • Maturation • Social and psychological development |
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Most children experience organized sport by 8-9 years, rates ________ during childhood and _________ post adolescence |
• Increase • Decrease - Similar decline in all physical activity |
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Participation in youth sports with age (2-5) |
• Most children can master many basic movements, but these should be practiced using free play rather than organized sports. Think activities such as throwing, running, kicking, catching a light ball, or pedalling with training wheels. |
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Participation in youth sports with age (6-7) |
• At this age, a child can usually understand a little about teamwork and better follow directions. This is when you can start considering an organized sport such as softball, soccer, gymnastics, swimming, tennis, or athletics. |
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Participation in youth sports with age (8-11) |
• A slightly older child is better able for a wider range of sports, including contact sports (with proper protective gear) such as basketball, hockey, or martial arts. |
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Participation in youth sports with age (11-12) |
• If your child is so inclined, this is the age at which they can normally take part in competitive sports, where keeping score and tracking wins and losses are essential |
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High school athletic participants by percentage and gender graph |
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What does the participation by gender title IX legislation (US, 1972) education amendments act state? |
•No person in the United States shall, on the basis of sex, be excluded from participation in, be denied the benefits of, or be subjected to discrimination under any education program or activity receiving federal financial assistance |
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What are the trends in Canada in regards to participation in youth sports? |
• In Canada, participation declined 1992 to 2005 in boys and girls • Most dramatic decline 11-14 year olds |
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What happens as sports climb the pyramid from recreational/novice → elite |
• ↑ demands - Commitment/resources • ↑ level of skill specialization • ↑ competition • Participant # ↓ |
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What are some reason for selection/exclusion in sport at as young as age 5? |
• Identification / selection • Systematic - Training / nutritional regulation/ academic accommodation • Selective / competitive recruitment - High school / collegiate / university coaches, pro sports |
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What are some key factors impacting the transition from a young athlete to an elite athlete? |
• Specialized skill • Maturity status may be a factor - Size, physique, performance • Timing and tempo of maturation • Transition to puberty may be limiting factor • Skill / physical characteristics • Initial 'access' to expert coaching → success |
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In general, athletes ________ average for stature and weight (50th to 90th percentile) |
• Above |
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Which sports are athletes not above average stature and weight? |
• Diving, gymnastics, figure skating, and ballet < 50th percentile for stature and weight • Female distance runners < 50th percentile for weight |
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What affect does a young athlete have on maturity status/PHV? |
• Childhood - No difference • Adolescence - Average / advanced maturity except gymnasts show later maturation • Pubertal progress boys and girls - Similar pattern as non-active • PHV-boys and girls age at PHV and magnitude of PHV similar to non-active - Except gymnasts age at PHV later than average |
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What is typically seen in age at menarche for female athletes? |
• Later average ages • Average age at menarche = 13 - 95% of girls = 11-15 |
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Do sports like gymnastics, figure skating, ballet select late-maturing OR do early-maturing girls selectively drop out? |
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Female youth athletes on body composition |
• Lower relative fatness • Little variation with age in athletes • Greater difference between athletes and non athletes than in males |
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Males youth athletes on body composition |
• Relative decline in fatness with age • Athletes less relative fatness at most ages |
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Effect of youth athletes on motor performance for vertical jump? |
• Diving exceed non-athletes for all ages - Focus of training • Downhill skiers are similar to non-athletes - Side-to-side jumping • Distance runners are similar to non-athletes to age 13 - Lag behind non-athletes (no explosive training) |
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Youth athletes on relative VO2 |
• Greater relative VO2 - Males progressive ↑ to adolescence • Female swimmers / distance runners - Greater VO2 than non-athletes similar to males non-athletes |
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What effect does endurance training have on young athletes? |
• Taller/larger • Greater heart volume - Left ventricular diameter - Training bradycardia (resting) • > blood volume, hemoglobin, lung volumes • Persistence of > physiological parameters • 5 years post training - V02 reduced 30% - Hemoglobin reduced 13 % - Maintained blood and lung volumes |
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Differences between gymnastics and ballet schematic |
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Toffler stated training more than 18 hours per week before and during puberty may alter the growth rate and prevent full attainment of full adult height, what does research show? |
• Female gymnasts exhibit similar pattern of growth / maturation as short, normal slow-maturing girls of short parents (SA, PHV timing / magnitude)stature deficit apparent by age 2 in short, normal slow-maturing girls |
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Is the same true for young male gymnasts? |
• Similar pattern of growth / maturity of short, slow-maturing boys of parents with short stature • Differential drop out - Not all gymnasts persist in the sport • Dropouts - Taller, heavier,advanced maturity compared to those who continued - Suggests training had an influence |
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What is the growth pattern of female ballet dancers? |
• Similar to that of late-maturing girls - Early adolescent short stature catch up and later attainment adult stature - SA behind CA, later sexual maturity - Decline in weight-for-height during puberty - Concern for body weight → eating disorders |
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What are the key points to be noted between young athletes and non-athletes? |
• Young athletes grow similar to non-athletes • Training does not accelerate / decelerate stature / skeletal, sexual, somatic maturity • Training can positively impact body composition, physiological parameters, performance |
