Physiological Changes: Health-Related Physical Fitness Chapter 7 Copyright © 2016 by Holcomb Hathaway Publishers

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 Copyright © 2016 by Holcomb Hathaway Publishers

Cardiorespiratory Fitness Delivery of oxygen to muscle tissues to maintain physical work Physiological parameters: Heart rate Stroke volume Cardiac output Maximal oxygen consumption (VO2max) Copyright © 2016 by Holcomb Hathaway Publishers

by Holcomb Hathaway Publishers 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) Copyright © 2016 by Holcomb Hathaway Publishers

by Holcomb Hathaway Publishers 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 Copyright © 2016 by Holcomb Hathaway Publishers

by Holcomb Hathaway Publishers 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 Copyright © 2016 by Holcomb Hathaway Publishers

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 Copyright © 2016 by Holcomb Hathaway Publishers

Aerobic Capacity of Adolescents, Men, and Women Copyright © 2016 by Holcomb Hathaway Publishers

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? Copyright © 2016 by Holcomb Hathaway Publishers

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. Copyright © 2016 by Holcomb Hathaway Publishers

by Holcomb Hathaway Publishers 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 Copyright © 2016 by Holcomb Hathaway Publishers

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 Copyright © 2016 by Holcomb Hathaway Publishers

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 Copyright © 2016 by Holcomb Hathaway Publishers

Muscular Strength Training Maturity level affects training outcomes Prepubescence Adolescence/early and middle adulthood Late adulthood Copyright © 2016 by Holcomb Hathaway Publishers

Selected Weight-Resistance Guidelines for Children Copyright © 2016 by Holcomb Hathaway Publishers

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? Copyright © 2016 by Holcomb Hathaway Publishers

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). Copyright © 2016 by Holcomb Hathaway Publishers

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 Copyright © 2016 by Holcomb Hathaway Publishers

by Holcomb Hathaway Publishers 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 Copyright © 2016 by Holcomb Hathaway Publishers

by Holcomb Hathaway Publishers 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. Copyright © 2016 by Holcomb Hathaway Publishers

by Holcomb Hathaway Publishers 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 Copyright © 2016 by Holcomb Hathaway Publishers

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 Copyright © 2016 by Holcomb Hathaway Publishers

NHANES – Prevalence of Obesity* Among U.S. Children and Adolescents Copyright © 2016 by Holcomb Hathaway Publishers

Age-Adjusted Prevalence of Obesity in Adults (U.S., 2011/2012) Copyright © 2016 by Holcomb Hathaway Publishers

by Holcomb Hathaway Publishers Age-Adjusted Prevalence of Obesity in U.S. Adults, by Sex, Race, and Hispanic Origin (2011/2012) Copyright © 2016 by Holcomb Hathaway Publishers

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. Copyright © 2016 by Holcomb Hathaway Publishers

Laboratory- and Field-Test Measures of Body Composition Hydrostatic weighing Bod pod Field: Skinfold calipers Source: From Housh et al., 2016. Used with permission. Copyright © 2016 by Holcomb Hathaway Publishers

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 Copyright © 2016 by Holcomb Hathaway Publishers

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? Copyright © 2016 by Holcomb Hathaway Publishers