Download Ch11

Training Considerations
for Special Populations
CHAPTER OBJECTIVES
• Understand that not everyone should be presented
with the same exercise stimulus.
• Describe the physiological differences that exist
between men and women that might affect exercise
prescription.
• Discuss the limitations that pregnancy might place
on a woman’s capacity to exercise safely.
• Describe what factors must be considered when
designing exercise programs for children and older
adults.
Introduction to Sex Differences in
Sport and Exercise
• For decades, culture, athletic governing
bodies, and PE curricula perpetuated the
myth that girls and women should not
compete in sport
• Last 30 to 40 years, girls and women have
achieved great athletic feats
– Sex differences in performance still exist
– Separating biological versus other factors
Body Size and Composition
• Testosterone leads to
–  Bone formation, larger bones
–  Protein synthesis, larger muscles
–  EPO secretion,  red blood cell production
• Estrogen leads to
–  Fat deposition (lipoprotein lipase)
– Faster, more brief bone growth
• Shorter stature, lower total body mass
–  Fat mass, percent body fat
Physiological Responses
to Acute Exercise
• Muscle strength differs 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
Physiological Responses
to Acute Exercise
• Cardiovascular function differs greatly
• 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 , SV , cardiac output 
– Leads to  O2 consumption
Physiological Responses
to Acute Exercise
• Women compensate for  hemoglobin via
 (a-v)O2 difference (at submaximal
intensity)
– (a-v)O2 difference ultimately limited, too
– Lower hemoglobin, lower oxidative potential
• Sex differences in respiratory function
– Due to difference in lung volume, body size
– Similar breathing frequency at same relative
workload
– Women  frequency at same absolute workload
Physiological Responses
to Acute Exercise
• Women’s VO2max < men’s VO2max
• 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
Physiological Adaptations
to Exercise Training
• Body composition changes
– Same in men and women
–  Total body mass, fat mass, percent body fat
–  FFM (more with strength vs. endurance training)
• Weight-bearing exercise maintains bone
mineral density
• Connective tissue injury not related to sex
Physiological Adaptations
to Exercise Training
• Strength gains in women versus 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?
Physiological Adaptations
to Exercise Training
• Cardiorespiratory changes not sex specific
• Aerobic, maximal intensity
–  Qmax due to  SVmax ( preload, contractility)
–  Muscle blood flow, capillary density
–  Maximal ventilation
• Aerobic, submaximal intensity
– Q unchanged
–  SV,  HR
Physiological Adaptations
to Exercise Training
• VO2max changes not sex specific
– ~15 to 20% increase
–  Qmax,  muscle blood flow
– Depends on training intensity, duration, frequency
• Lactate threshold 
• Blood lactate for given work rate 
• Women respond to training like men do
Effect of Menstruation on
Performance
• 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
Female Athlete Triad
• Amenorrhea
• Osteoporosis
• Disordered Eating
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:  caloric intake,  activity (in
some cases)
Pregnancy Recommendations
• Moderate exercise 3x/week
– Reduces T3DM risk
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Resistance training recommended
Ensure adequate caloric intake
No supine exercise after first trimester
Non-weight-bearing exercise preferable
No risk of falling, loss of balance, etc.
Decrease vigorous exercise in third
trimester
Children and Exercise
• Historic reflections on exercise and
resistance training outdated
• Cardiovascular differences
– ↓ heart size, ↑ HR both at rest and during ex
– Limited anaerobic energy supply
• ↓ blood lactate
• ↓ glycolyic enzymes
• Hyperthermia risk ↑ due to less efficient
sweat mechanism
Children and Exercise
Older Adults and Exercise
• ↓ in physiological capacity is inevitable
• “Psychomotor Slowing”
– Cardiovascular
• ↓ in Q, SV, HRmax, VO2max, a-vO2 diff
– Sarcopenia - Skeletal muscle loss results in ↓
isometric and dynamic muscle strength
• Apoptosis
– Bone mineral density ↓
Older Adults and Exercise
• Baseline assessment for everyone
• Aerobic prescription – 150+ minutes of
moderate aerobic activity/wk
• Resistance exercises on 2 or more days a
week that work all the major muscles (1s, 1015r).