1. Physiological Changes: Health-Related Physical Fitness
Chapter 7
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2. Physical Activity and Health
Maintaining an active lifestyle is linked to good health.
Physical Activity Guidelines for Americans
Components of health-related fitness:
Cardiorespiratory fitness
Muscular strength
Flexibility
Body composition
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3. Cardiorespiratory Fitness
Delivery of oxygen to muscle tissues to maintain physical work
Physiological parameters:
Heart rate
Stroke volume
Cardiac output
Maximal oxygen consumption (VO2max)
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Heart Rate
The number of times the heart beats each minutes
Undergoes much change throughout the lifespan
For young/middle-aged adults:
Maximal HR = 220 – age (years)
For older adults:
HRmax = 208 – 0.7 x age (years)
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Stroke Volume (SV)
Blood that is ejected from left ventricle into general circulation via the aorta
Size is limited by many factors:
Heart size, contractile force of the myocardial tissue, vascular resistance to blood flow, and venous return
Substantially lower in children than in adults
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Cardiac Output
The amount of blood that can be pumped out of the heart in 1 minute
Heart rate  stroke volume
Lower in children than for adults; decreases with age
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7. Maximal Oxygen Consumption
Largest amount of oxygen a human can consume at the tissue level
Best single measure of physical working capacity
With age, the body’s ability to acquire and deliver oxygen to working tissues is altered, reducing physical work capacity
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8. Aerobic Capacity of Adolescents, Men, and Women
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9. Cardiorespiratory Fitness in U.S. Children and Adolescents
After reading about the state of cardiorespiratory fitness in American children and adolescents as of 2012, as described on page 156 of the text, are you surprised by the findings?
If a similar assessment were done today, what do you think the findings would be?
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10. Physical Activity and Cardiorespiratory Fitness in Adulthood
General agreement on how a young to middle- aged adult can attain beneficial effects from aerobic exercise:
Individual must perform large-muscle activities 3 to 5 days/week for 20 to 60 minutes at an HR intensity of 60 to 90 percent of maximum.
Less is known about late adulthood.
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Muscular Strength
Strength: The ability to exert muscular force
Static or isometric
Dynamic
Necessary for the execution of all motor tasks
Each human movement requires different degrees of strength
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12. Grip Strength—A Measure of Muscular Strength
Increases significantly between ages of 7–17
Gender differences after puberty
Remains relatively constant in early and middle adulthood
Acceleration of muscle mass loss after age 50
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13. Muscular Strength in U.S. Children and Adolescents
National Youth Fitness Survey (2012):
No significant differences by gender in various measures of strength for preadolescent children
Adolescent boys had higher values than girls on all measures
Modified pull-ups: Adolescent boys completed more than younger boys; there was no significant difference for girls of various age groups
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14. Muscular Strength Training
Maturity level affects training outcomes
Prepubescence
Adolescence/early and middle adulthood
Late adulthood
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15. Selected Weight-Resistance Guidelines for Children
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16. Reflecting on Children and Strength Training
Your brother likes to lift weights using various barbells stored in his garage; his 8-year-old son often watches and decides he’d like to take up weight lifting as well.
How do you advise your brother and your nephew about the safety of strength training for a boy his age?
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17. Resistance Training—Guidelines for Healthy Adults
8 to 10 exercises for the body’s major muscle groups
Minimum of twice a week
Minimum of one set with 8–12 repetitions
For older adults, improvements in muscular strength and endurance help with activities of daily living (see Chapter 15).
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18. Mechanisms of Increasing Muscular Strength
Hypertrophy: Increases to the size of the muscle and the specific tensions that can be exerted within the muscle
Neural adaptations that result in an increased ability of the nervous system to activate muscle tissue
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Flexibility
Performing daily activities requires the ability to bend various body parts and joints smoothly.
Flexibility: The range of movement within joints
Regionally specific
Sit-and-reach test
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Flexibility Trends
Peak flexibility is achieved in late teens or early 20s
Girls of all ages are more flexible than boys
Decreases with age
Physical activity is necessary
to maintain joint mobility.
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Body Composition
Sedentary lifestyle leads to excess fat and serious health consequences:
E.g., high blood lipid levels, elevated blood pressure, cardiovascular disease, metabolic disease
Overweight and obesity: Amount of body fat greater than is considered healthy
Body mass index: See Chapter 6
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22. General Growth Trends of Adipose Tissue
Prenatally: Subcutaneous adipose tissue appears
At birth: 11% fat for boys; 14% for girls
Puberty: Young but mature female adolescent has a body-fat content 50% greater than male counterpart
Ideal body fat: 10–25% for men and 18–30% for women
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23. NHANES – Prevalence of Obesity* Among U.S. Children and Adolescents
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24. Age-Adjusted Prevalence of Obesity in Adults (U.S., 2011/2012)
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Age-Adjusted Prevalence of Obesity in U.S. Adults, by Sex, Race, and Hispanic Origin (2011/2012)
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26. Association Between Childhood and Adulthood Obesity
“Childhood BMI (weight) is a strong predictor of obesity in adulthood.” (Magarey, Daniels, Boulton, & Cockington, 2003)
Children with BMI values at the 95th percentile for age/gender have a greater than 60% chance of being obese at age 35.
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27. Laboratory- and Field-Test Measures of Body Composition
Hydrostatic weighing
Bod pod
Field:
Skinfold calipers
Source: From Housh et al., 2016.
Used with permission.
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28. Relationship of Obesity to Motor Development and Performance/Fitness
High subcutaneous fat and overweight were associated with delayed infant motor development
Strong negative correlation between BMI and endurance performance
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29. Reflecting on Interactive Technology
Do you use a fitness tracker to track activity or count daily steps?
Do you use a fitness app to track activity, map a route, or log food?
If so, what has your experience been with them? Do they help motivate you to exercise more and be more health conscious?
If not, do you have another method for motivating yourself to be more active?
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by Holcomb Hathaway Publishers