Age and Sex Considerations in Sport and Exercise Flashcards
What are some physiological responses to acute exercise when a person is growing?
• Strength • Cardiovascular, respiratory function • Metabolic function – Aerobic capacity – Running economy – Anaerobic capacity – Substrate utilization • Strength as muscle mass with age – Peaks at ~20 years for women – Peaks at 20 to 30 years for men • Strength, power, skill require myelination – Peak performance requires neural maturity – Boys experience marked change at ~12 years – Girls more gradual, linear changes
What are some physiological responses in terms of the CV system when a person is growing?
• Resting and submaximal blood pressure
– Lower than in adults (related to body size)
– Smaller hearts, lower peripheral resistance during
exercise
• Resting and submaximal stroke volume, HR
– Lower SV: smaller heart, lower blood volume
– Higher HR: almost compensates for low SV
– Slightly lower cardiac output than an adult
– (a-v-)O2 difference will increase to further compensate
• Maximal HR higher than in adults
• Maximal SV lower than in adults
• Maximal cardiac output lower
– Limits performance: less O2 delivery
– Not a serious limitation for relative workloads
What are some physiological responses to acute exercise in terms of lung function when a person is growing?
• Lung function – Lung volume increases with age – Peak flow rates increase with age – Postpuberty: girls’ absolute values lower than boys’ due to smaller body size
What are some physiological responses to acute exercise in terms of metabolic function when a person is growing?
– Increases with age
– Related to muscle mass, strength, cardiorespiratory
function
What are some CV changes in response to acute exercise in a growing person?
• Cardiorespiratory changes during exercise
accommodate muscles’ need for O2
• Cardiorespiratory changes with age permit
greater delivery of O2
– V•O2max in L / min increases with age (boys, girls)
– V•O2max in ml / kg / min steady with age in boys
– V•O2max in ml / kg / min decreases with age in girls
– L / min more appropriate during growth year
How would one approach scaling data for size?
• V•O2max relative to body weight is
considerably different from absolute values,
as shown in figure 17.7
• Using body surface area or weight to the
0.75 power is the best way to reduce the
effect of body size on data
What are some physiological responses to acute exercise in children?
• Children’s economy of effort worse than
adults’
– Child’s O2 consumption per kilogram > adult’s
– With age, skills improve, stride lengthens
• Endurance running pace increases with age
– Purely result of economy of effort
– Occurs regardless of V•O2max changes, training
status
Explain the differences between a child’s vs. an adult’s anaerobic capacity for exercise?
• Children limited anaerobic performance compared to adults • Lower glycolytic capacity in muscle – Less muscle glycogen – Less glycolytic enzyme activity – Blood lactate lower – Mean and peak power increase with age • Resting stores of ATP-PCr similar to adults’
What are the endocrine responses to acute exercise in a child?
– Exercising growth hormone and insulin-like growth
factor surge higher than in adults
– increased Stress response to exercise compared to adults
– Hypoglycemic at exercise onset
– Immature liver glycogenolytic system
What are substrate utilisation responses to acute exercise in a child?
– Relies more on fat oxidation compared to adults
– Exogenous glucose utilization high
How do body weight & composition respond to physical training in a child?
– Respond to physical training similarly to adults
– Training - decreased body weight/fat mass, increased FFM
– Significant bone growth
Is weight lifting safe for children to engage in?
• Weight lifting safe and beneficial – Should be prescribed, supervised – Low risk of injury – Protects against injury – Child: strength gains only via neural mechanisms, no hypertrophy – Adolescent: neural + hypertrophy
Describe some changes in regards to aerobic training in children?
– Little or no change in V•O2max
– Performance increased due to improved running economy
Describe some changes in regards to aerobic training in adolescents?
– More marked change in V•O2max
– Likely due to increase in heart size, SV
What are some physiological responses to anaerobic training in a child?
– increased Resting PCr, ATP, glycogen
– increased Phosphofructokinase activity
– increased Maximal blood lactate
Can adult anaerobic training programs be utilised to train a child?
• Adult anaerobic training programs can be
used with children and adolescents
– Be conservative to reduce risk of overtraining, injury,
loss of interest
– Explore variety of activities and sports
What are the typical physical activity patterns among youth?
• Physical activity patterns established in
childhood carry into adulthood
• Intervention strategies aimed at getting
children more active have been mostly
ineffective
Explain sports performance and specialisation in children/young adults?
• Sport performance in children and
adolescents improves with growth and
maturation
• Early specialization in one sport reduces
“fun” physical activities - reduced lifelong
physical activity
Explain thermal stress in children?
– Children have a larger surface area:mass ratio
– decreased Evaporative heat loss (less sweat)
– Slower heat acclimation
– Greater conductive heat loss, gain
• More research needed; be conservative
Explain a child’s growth when training?
– Little or no negative effect on height
– Affects weight, body composition with intensity
– Peak height velocity age unaffected
– Rate of skeletal maturation unaffected
• Maturation with training: effects on markers
of sexual maturation less clear
Explain the chantes in height, weight and body composition in an aging person.
• Height decreases with age
– Starts at 35 to 40 years
– Compression of intervertebral discs
– Poor posture
– Later, osteopenia, osteoporosis
• Weight increases, then decreases
– increases 25 to 45 years: decreased physical activity, increased caloric intake
– decreases 65+ years: loss of body mass, less appetite
• Body fat content tends to increase
– Active versus sedentary older adults vary
– Older athletes have lower body fat content
– Older athletes have lower central adiposity
• Fat-free mass decreases starting around age 40
– decreased Muscle, bone mass
– Sarcopenia (protein synthesis decreases)
– Due (in part) to lack of activity
– decreased Growth hormone, insulin-like growth factor 1
• Bone mineral content decreases
– Bone resorption > bone synthesis
– Due to lack of weight-bearing exercise
• Body composition variables
– Body weight
– Percent body fat
– Fat mass
– Fat-free mass (FFM)
How does training alter age-related body composition changes?
– decreased Weight, percent body fat, fat mass
– increased FFM (more likely with resistance training than with aerobic training)
– Men > women
• Biggest results with diet + exercise
Describe the physiological responses to acute exercise in an aging person.
• Strength and neuromuscular function decrease
with age
– Interferes with activities of daily living
– Manifests ~50 to 60 years of age
– Results from decreased muscle mass
• Strength decrease offset by resistance exercise
• Type II fiber loss with aging
– Decrease in type II motor neurons
– Type I neurons innervate old type II fibers?
– Higher percent type I fibers
• Training slows or stops fiber-type change
• Size and number of muscle fibers decrease with
age
– Size of both type I and type II
– Lose 10% per decade after age 50
• Endurance training - no impact on decline
in muscle mass with age
• Resistance training - reduces muscle
atrophy, increased muscle cross-sectional area
• Reflexes slow with age
– Exercise preserves reflex response time
– Active older people ≈ young active people
• Motor unit activation decreases with age
– Exercise retains maximal recruitment of muscle
– Some studies show decreased strength due to local muscle (not neural) factors
• Exercise maintains muscle physiology
– Number of capillaries unchanged
– Oxidative enzyme activity only mildly reduced
What are some CV responses to acute exercise in an aging person?
• Central and peripheral cardiovascular
decrements with age
• Reduced maximal HR
– Reduction varies considerably
– Electrical and receptor changes with age
– Same for active and sedentary people
• HRmax = [208 – (0.7 x age)]
• Maximal stroke volume (SV) decreases with age
– decreased Contractility, response to catecholamines
– Partial loss of Frank-Starling mechanism
– LV, arterial stiffening
– Exercise attenuates decline in SVmax
• V•O2max decreased with age due to decreased Q•max
– Due more to decreased HRmax, less to decreased SVmax
– Exercise attenuates decline in V•O2max
• Sedentary habits increase risk for vascular aging
– decreased Cardiac and arterial compliance
– Endothelial dysfunction
– Reduced vasodilation
• Exercise -> decreased risk
– Less arterial stiffening, endothelial dysfunction
– Preserved vasodilator signaling
– Research ongoing on proper exercise dose for
cardiovascular benefit
• Peripheral blood flow decreases with age
– ~10 to 15% reduction even with exercise
– Due to increased vasoconstriction, decreased vasodilation
– increased (a-v-)O2 difference compensates for decreased flow
• Effects of primary aging versus
cardiovascular deconditioning
– Which changes result from aging alone?
– Which changes result from reduced activity?
What are some respiratory responses to acute exercise in an aging person?
• Respiratory function with sedentary aging
– decreased Vital capacity and FEV1.0, increased residual volume, total lung capacity unchanged
– Less air exchanged
– decreased Lung and chest wall elasticity with age
– But does not limit exercise capacity
• Exercise maintains ventilatory capacity
– Pulmonary ventilation does not limit aerobic capacity
– Oxygen saturation remains high
• V•O2max changes with aging
– Measured in L/min or ml/kg/min?
– Absolute versus relative decrement
• V•O2max in normally active older people
– Declines steadily from 25 years to 75 years
– ~1% per year (~10% per decade)
• V•O2max in older male athletes
– 5 to 6% decline per decade in active adults
– 3.6% decline over 25 years in elite athletes
– 15% decline per decade in previously active adults
• V•O2max in older female athletes
– Fewer studies, but similar to men
– ~1% decline per decade
– Longitudinal changes > cross-sectional changes
• Percent decline in V•O2max related to
intensity of training before and during aging
• Factors that affect rate of decline
– Genetics
– General activity level
– Intensity and volume of training
– Age-related body composition changes
– Age range
What are some changes in lactate threshold in response to acute exercise in an aging person?
• Lactate threshold (as % V•O2max) increases
– Not predictive of running performance with aging
– Percent V•O2max may not be best measure
– Remember: absolute V•O2 decreases with age
• Lactate threshold (as absolute V•O2) decreases
What are the effects of resistance training on an aging person?
• Effects of resistance training on strength
– increased Strength (men, women: 30%; some studies of men: 50-200+%)
– Fiber hypertrophy
– increased Cross-sectional area of types I, II
– Neural adaptations
• increased Muscle mass, muscle size, bone mineral
density
• Improved activities of daily living, decreased risk of
falls
What are VO2max improvements with training in an elderly population?
– Independent of sex, age, initial fitness
– Young: increased maximal cardiac output (central)
– Older: increased oxidative enzymes (peripheral)
What are some anaerobic capacity changes with training in an elderly population?
– Less known than aerobic training results
– Lactate threshold bad predictor of performance
Explain the changes of sports performance in an aging population.
• Running performance decreases with age.
– Rate of decline independent of distance
– Both 100 m, 10 km records slower with age
– Decline accelerates past age 60.
• Swimming performance decreases with age.
– Decline accelerates past age 70.
– Decline in women is greater than decline in men
• Cycling performance
– Peaks between 25 and 35 years
– Speed then decreases by 0.7% per decade
• Weight-lifting performance
– Peaks between 25 and 35 years
– Sum of power lifts then declines 1.8% per year
Explain any special issues e.g. hyperthermia & the risks associated in an elderly population.
• Higher risk of death from hyperthermia
– Higher core temperature than young subjects
– Metabolic heat gain related to absolute V•O2
– Heat loss related to relative percent V•O2max
• Physical training affects thermoregulation
– Improves skin vasodilation (convection)
– Improves sweat rate (evaporation)
– Improves redistribution of cardiac output
• Exercise in cold = increased risk of hypothermia
– Risk not as great as hyperthermia
– Reduced ability to generate metabolic heat
– Excessive convective heat loss
– Core temperature can drop even with mild cold
stress
• Must add behavioral thermoregulation
• Exercise and longevity
– Mild caloric restriction increases longevity
– Exercise may contribute to caloric balance
– Exercise - compression of mortality
• Exercise can lead to injury
– Tendon injury (rotator cuff, Achilles)
– Cartilage injury (meniscus, focal injuries)
– Stress fractures
• Exercise can reduce risk of falls
What is the difference between sex vs. gender?
• Sex is biologically determined. • Gender is culturally determined. • Most basic physiological comparisons to date have established sex differences. • IAAF policy on hyperandrogenism: Women must undergo testing if too “masculine.”
In relation to body size and composition, what is the effect of testosterone?
• Testosterone leads to
– increased Bone formation, larger bones
– increased Protein synthesis, larger muscles
– increased EPO secretion, increased red blood cell production
In relation to body size and composition, what is the effect of estrogen?
• Estrogen leads to – increased Fat deposition (lipoprotein lipase) – Faster, more brief bone growth – Shorter stature, lower total body mass – increased Fat mass, percent body fat
Explain body size and composition adaptations in females.
• Distinct female fat deposition pattern
• Rapid storage on hips and thighs due to increased
lipoprotein lipase activity
• decreased Lipolytic activity makes regional fat loss
more difficult
• Lipoprotein lipase decreases, lipolysis increases during third trimester of pregnancy, lactation
How does muscle strength differ between sexes?
– Upper body: women 40 to 60% weaker
– Lower body: women 25 to 30% weaker
– Due to total muscle mass difference, not difference
in innate muscle mechanisms
• No sex strength disparity when expressed
per unit of muscle cross-sectional area
What are the causes of upper body strength disparity?
– Women have more muscle mass in lower body – Women utilize lower body strength more – Altered neuromuscular mechanisms? • Women: smaller cross-sectional areas • Similar fiber-type distribution • Research indicates women more fatigue resistant
How does cardiovascular function differ between the genders?
• For same absolute submaximal workload
– Same cardiac output
– Women: lower stroke volume, higher HR
(compensatory)
– Smaller hearts, lower blood volume
• For same relative submaximal workload
– Women: HR slightly higher , SV lower, cardiac output lower
– Leads to decreased O2 consumption
• Women compensate for decreased hemoglobin via increased (a-v-)O2 difference (at submaximal
intensity)
– (a-v-)O2 difference ultimately limited, too
– Lower hemoglobin, lower oxidative potential
What are some sex differences in terms of respiratory function?
– Due to difference in lung volume, body size
– Similar breathing frequency at same relative
workload
– Women increase frequency at same absolute workload
• Women’s V•O2max < men’s V•O2max
• Untrained sex comparison unfair
– Relatively sedentary nonathlete women
– Relatively active nonathlete men
• Trained sex comparison better
– Similar level of condition between sexes
– May reveal more true sex-specific differences
• Can scale V•O2max to other body variables
– Height, weight, FFM, limb volume
– Sex difference minimized or gone with scaling
• Simulated women’s fat mass on men
– Reduced sex differences in treadmill time,
submaximal V•O2(ml / kg), V•O2max
– Women’s additional body fat major determinant of
sex-specific difference in metabolic responses
• Women’s lower hemoglobin limits V•O2max
• Women’s lower cardiac output limits V•O2max
– SVmax limited by heart size, plasma volume
– Plasma volume loading in women helps
– Submaximal absolute V•O2: no sex difference in SV
• Sex differences in lactate, threshold
– Peak lactate concentrations lower in women
– Lactate threshold occurs at same percent V•O2max
What are some changes in body composition between the sexes?
• Body composition changes
– Same in men and women
– decreased Total body mass, fat mass, percent body fat
– increased FFM (more with strength vs. endurance training)
• Weight-bearing exercise maintains bone
mineral density
• Connective tissue injury not related to sex
Explain strength gains in women vs. men?
– Less hypertrophy in women versus men, though
some studies show similar gains with training
– Neural mechanisms more important for women
• Variations in weight lifted for equivalent
body weight
– For given body weight, trained men have more FFM
than trained women
– Fewer trained women
– Factors other than FFM?
Explain cardiorespiratory changes in the sexes? Are these changes sex-specific?
• Cardiorespiratory changes not sex specific
• Aerobic, maximal intensity
– increased Q•max due to increased SVmax (increased preload, contractility)
– increased Muscle blood flow, capillary density
– increased Maximal ventilation
• Aerobic, submaximal intensity
– Q• unchanged
– increased SV, decreased HR
Explain VO2max changes between the sexes? Are these changes sex-specific?
• V•O2max changes not sex specific
– ~15 to 20% increase
– increased Q•max, increased muscle blood flow
– Depends on training intensity, duration, frequency
• Lactate threshold increased
• Blood lactate for given work rate decreases
• Women respond to training like men do
Explain sports performance differences between the sexes.
• Men outperform women by all objective standards of competition – Most noticeable in upper-body events – Gap narrowing • Women’s performance drastically improved over last 30 to 40 years – Leveling off now – Due to harder training
Explain menstruation and athletic performance in females?
• Normal menstrual function
– Menstrual (flow) phase
– Proliferative phase (estrogen)
– Ovulation—follicle stimulating hormone (FSH),
luteinizing hormone (LH)
– Secretory phase (estrogen, progesterone)
• Cycle length ~28 days, can vary
• No reliable data indicate altered athletic
performance across menstrual phases
• No physiological differences in exercise
responses across menstrual phases
• World records set by women during every
menstrual phase
Explain menstrual dysfunction and athletic performance in females?
• Menarche: first menstrual period – May be delayed in certain sports (e.g., gymnastics) – Delayed menarche: after age 14 • Delayed-menarche athletes self-select? – Sport may not - delayed menarche – Small, lean athletic girls (delayed menarche candidates) may gravitate to sport • Menstrual dysfunction – Seen more in lean-physique sports – Eumenorrhea: normal – Oligomenorrhea: irregular – Amenorrhea (primary, secondary): absent – Can affect 5 to 66% of athletes • Menstrual dysfunction ≠ infertility • Secondary amenorrhea—caused by energy deficit (inadequate caloric intake) – decreased LH pulse frequency – decreased T3 secretion – decreased Estrogen, progesterone – May also involve GnRH, leptin, cortisol • As long as caloric intake adequate, exercise does not lead to secondary amenorrhea
Explain any pregnancy concerns?
- Acute reduction in uterine blood flow
(shunt to active muscle) -> fetal hypoxia - Fetal hyperthermia from increase in
maternal core temperature - Maternal CHO usage increased, thereby decreasing CHO availability to fetus
- Miscarriage, final outcome of pregnancy
• decreased Uterine blood flow may not lead to hypoxia
– Uterine (a-v-)O2 difference increase may compensate
– Fetal HR increases due to maternal catecholamines
• Fetal hyperthermia: unresolved
• CHO availability: unresolved
• Miscarriage, final pregnancy outcome
– Data scarce, conflicting
– Many studies show favorable (or no) effects
Explain physical activity recommendations for pregnant women?
• Mild-to-moderate exercise 3 times / week
• No supine exercise after first trimester
• Stop when fatigued
• Non–weight-bearing exercise preferable
• No risk of falling, loss of balance, etc.
• Ensure adequate caloric intake
• Dress and hydrate to avoid heat stress
• Prepregnancy exercise routine should be
gradually resumed postpartum
• No scuba diving
• Benefits > risks if cautiously undertaken
Explain osteopenia & osteoporosis and how hormone deficiencies contribute to these diseases (risk factors between the sexes?)
• Osteopenia versus osteoporosis – Risk greater in women especially after menopause – Slowed and retarded by weight-bearing exercise • Major contributing factors – Estrogen deficiency – Inadequate calcium intake – Inadequate physical activity – Amenorrhea, anorexia nervosa • Physical activity affects bone health – Maximize bone density early in life – Diet, weight-bearing physical activity • Menstrual status affects bone health – Particular concern for postmenopausal women; exercise can protect against bone loss – Women with amenorrhea or anorexia nervosa often suffer low bone mass
Explain eating disorders and risk factors between the sexes.
• Anorexia nervosa
– Refusal to maintain minimal normal weight
– Distorted body image, fear of fatness
– Amenorrhea
• Bulimia nervosa
– Recurrent binge eating
– Lack of control during binges
– Purging behaviors (vomiting, laxatives, diuretics)
• Young women at highest risk
• Eating disorder versus disordered eating
• Worse in certain sports
– Appearance sports: diving, figure skating, ballet
– Endurance sports: distance running, swimming
– Weight-class sports: jockeys, boxing, wrestling
– Perfectionists, competitive, under tight control
• Self-reporting underestimates prevalence
• Eating disorders considered addictions
– Behavior reinforced by media, parents, coaches
– Very difficult to treat
– Often accompanied by denial
– Life threatening, expensive to treat
• Must seek out trained clinical specialist
What is the Female Athlete Triad?
• Syndrome of interrelated conditions
– Energy deficit secondary amenorrhea low
bone mass
– Disordered eating may (not) be involved
• Three disorders can occur alone or in
combination, must be addressed early
• Treatment: increased caloric intake, decreased activity (in
some cases)
What is menopause & how can exercise be utilised for this condition?
• Usually occurs between ages 45 and 55
• Symptoms can lower quality of life in some
• Exercise is recommended to improve mood,
decrease depression, and improve sleep
