2nd 30 Flashcards
Order of Growth: Length Breadth Diameter of wall Calcification
Repeat
Until mature
Bone Growth
Factors influencing bones
Heredity
Physical activity <- environment
Nutrition ß environment
Grean leafy vegetables
Dairy
Strong bones
1.5 hours of weight-bearing activity (load the bones) daily
Normal diet (healthy)
Sunlight and vitamin D
Environment
Goal is high fracture point Bend more, break less What contributes? Bone size (breadth) Bone density Bone thickness (diameter)
Fracture point
When does it begin? 35,55,75?
Bone loss is greater than gain after age 35 years
Less replacement in the inactive adult
3% of decalcification by astronauts in 4-14 days
Muscle loss begins in men at age 20 years
Muscle loss in women begins at 40 years
Aging
1 cm per decade after age 40
More rapid after age 70
1-3 inches loss depending upon how long you live!
Stature
Increases in men to age 55, women age 65
May increase as much as 30%
Central fat (around organs) increase
Subcutaneous fat decreases with advancing age
Body Fat
The muscle mass was significantly associated with serum free-tester one, physical activity, cardiovascular disease, and IGF1 in the men
In women, the muscle mass was significantly associated with total fat mass and physical activity. Estrogen was not associated with muscle mass or strength in women
Physical activity is an important predictor of muscle mass in both sexes.
Predictors of skeletal muscle mass in elderly men and women.
Loss of muscle mass is associated with the decline in strength in older adults; strength decline is much more rapid than loss of muscle mass
Suggesting a decline in muscle quality
Maintaining or gaining muscle mass does not prevent aging-associated declines in muscle strength
Both men and women lost strength, with men losing almost twice as much strenght as women.
Blacks lost about 28% more strength than did whites.
Longitudinal study
65 years and above
150 minutes of moderate intensity aerobic physical activity each week or 75 minutes of vigorous
(Minimum of 10 minutes per bout Additional benefits from 300 and 150 respectively )
With poor mobility should perform activities to improve balance and prevent falls 3 days per week
Muscle strengthening 3 or more days per week
If you cant do this, do as much as possible
World health organization
Lower rates of CVD, certain cancers, diabetes
Healthier body mass and composition
Healthier bones
Higher levels of functional health, a lower risk of falling, better cognitive function.
Reduced depression.
Benefits for older adults
Never too late to start
Mental health
Reduced disease
Healthier body
Older Adults
Sarcopenia, or the gradual loss of muscle mass, is a common consequence of aging
Hormones
Activity
Anthropometric Aging
Max VO2 declines in older adults: loss of skeletal muscle
Muscle decreases strength decreases more rapidly
Why?
Older adults have reduced muscle mass Predicts Max VO2 Enhances balance Older adults are afraid of falling Older adults are less active
Performance and Anthropmetry
Each of you is getting older
Currently more than 35 million people over 65 years old
By 20130 that will be over 70 million
Living longer but not better
Increased prevelance of chronic disease
Health care costs escalating
Quality of life poor at the end
Why is aging important?
Biological (physical domain)
Developmental (not miniature adults)
Individual (structural)
Physiology
Cardiovascular
Aerobic Anaerobic Muscle strength Flexibility Body composition
Underlying systems
Goal is meeting the physical activity guidelines
Understand underlying factors that may influence children (and not adults) or
Factors that do not change across childhood
Why physiology
How do we examine change?
BA (biological age)
Ca (chronological age)
Size (body surface
To what do we compare Genders Adults Young adults Trained and untrained kids or adults
What else to consider
Seated versus supine
Relative versus absolute strength
Developmental physiology
Heart rate (decreases)
Stroke volume (increases)
Cardiac output (increases=SV *HR
Maximal oxygen consumption
Two factors during childhood that determine Max VO2
Aerobic enzyme activity (decreases as body size increases)
Skeletal muscle (increases)
Cardiovascular development
System grows that determines Max V02
Lungs
Heart
Skeletal muscle
Therefore maximal aerobic power increases during childhood
Between 6 and 12 years of age boys double aerobic capacity
Girls are lower (200ml/min lower
Males increase dramatically at puberty
Females plateau at puberty
When corrected for size
Males steady durin childhood (50-52 mlKg)
Females decline from age 8 years on through 15 where m=42 Mlkg
Aerobic Capacity
So, girls
Max V02 increases at puberty (and levels)
Relative to body mass it decreases 2 years before and after menarche
What about fat?
1/m/kg produces ~ 17% gender difference
1/m/kg lbm produces at 6% gender difference
So the underlying cardiovascular gender differences are small
Performance difference are larger
.
Other cardiovascular issues
Children have less hemoglobin per unit of blood
Must pump more blood to deliver same oxygen
At rest children “work harder” than adults
Younger children have less skeletalal mass than older children
Capillaries increase during childhood
Less muscle and less capacity to deliver oxygen
Running Economy increases during childhood
.
Endurance improves
Sub-maximal endurance is not predicted by V02 max
Habitual activity does not predict in kids
Exercise economy does not predict exercise endurance
Correcting for size and fat males and females have similar endurance
True VO2 max “gender” difference is about 5% in children
Peripheral factors do predict age realted changes in performance
Skeletal muscle pumps blood back to heart
Arteriolar dilation
.
Strength is one repetition maximum
Endurance is number or % of max that can be repeated
strength and endurance
Related to the cross-sectional size of the muscle
Number of fibers
Size (hypertrophy) of fibers
More and/or larger fibers=stronger
For specific task other factors include
Training
Length of levers
Strength
Corrected for weight - no difference
Body dimensions also a factor (shorter levers)
Corrected for size is better correlated to field measure
Circum-pubertal responses to training
Less benefit from training
Focus on endurance (low resistance, high repetitions)
Increased number of muscle fibers
Muscle strength
Mile run or pacer
Sit up or curl up (abdominal endurance)
Pull up, arm hang or push up (upper body endurance)
Fitness in youth
Vertical jump, horizontal jump
Push ups, pull ups
These have a “skill” component
Most strength tests have a learning curve
First 3 weeks of training the increase is technique
After 8 weeks the increases is likely muscle related
Field tests
Three levels
Presidential physical fitness award (85th percentile)
National fitness award (50th percentile)
Participant physical fitness award (does all events but is
President challenge
Pacer or mile run Pull-ups or push ups Curl ups Chest lifts Back saver sit and reach BMI or skin folds
Fitnessgram test
A lack of high-quality studies supporting a strong link between any specific musculoskeletal fitness test item and health outcomes in youth
The link between musculoskeletal fitness and health in adults has extended beyond low-back health to other outcomes, such as personal independence and quality of life, cardiovascular dieasese, risk of fracture, and cognitive functional ability
Musculoskeletal fitness
