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Physical Activity
Any form of muscular movement– Related to physical fitness
Exercise – A subset of physical activity for the purpose of
maintaining or improving physical fitness Can reduce the risk of death from all causes Physical inactivity is a primary risk factor for
coronary heart disease
Dose-Response Relationship of Drugs (an example)
The effect (response) of the amount of a drug (dose)– Potency – how much an amount can effect– Slope – change in effect from change in dose– Maximal effect – the most it can do– Variability – different for different people– Side effect – other unwanted action
The Exercise Dose – F.I.T.
Frequency– Number of days per week– Number of times per day
Intensity– Percent VO2max or VO2 reserve
– Percent maximal HR or heart rate reserve– Rating of perceived exertion– Lactate threshold
Time (duration)– Number of minutes of exercise– Total kcals expended – Total kcals per kg body mass
The Response to Exercise
Improving fitness– Thereby improving health
Improving fitness and health– Simultaneously or separately
Improving fitness– But not a specific health outcome
Improving a specific health outcome– But not improving fitness
Patterns in the Response to Exercise
Acute responses– Occur within one or several exercise bouts
but does not improve further Rapid responses
– Benefits occur early and plateau Linear
– Gains are made continuously over time Delayed
– Occurs only after weeks of training
Physical Activity and Health
The benefits of physical activity may be more related to total number of calories expended than exercise intensity
The “Exercise Lite” recommendation
“Every U.S. adult should accumulate thirty minutes or more of moderate-intensity
(3-6 METs) physical activity on most, preferably all, days of the week.”
Benefits of Improving Fitness
In previously sedentary subjects– Small changes in physical activity result in
large health benefits with minimal risk– Strenuous exercise
Increases the risk of a heart attack during activity– Reduces overall risk (rest + exercise)
Moderate to high levels of fitness– Reduce the risk of death from all causes
General Guidelines for Improving Fitness Screening
– Health status screening (PAR-Q) Progression
– Start with low-intensity exercise (walking)– Then increase duration and/or intensity
Warm-up, cool-down, and flexibility– Light exercise and flexibility performed at
beginning and end of exercise session
Exercise Prescription for Cardiorespiratory Fitness 200-300 kcals per session Considerations
– Weight loss– Improved fitness– Injury prevention
Frequency Intensity Time (duration)
Exercise Intensity
Corresponding to 60-80% VO2max
Target heart rate (THR) range– Direct method
• HR at percentage of maximal work rate found during GXT
– Indirect method• 70-85% of maximal HR• 60-80% of HR reserve (Karvonen) method
.
Sequence of Physical Activity
Walking– Start at a comfortable speed for 15 minutes– Gradually increase duration and speed
Jogging– Start by adding some running when walking– Gradually increase speed/duration of running
Games and sports– Intermittent higher-intensity activities within THR
range
Strength Training
Muscular strength is an important component of physical fitness– Strength to do
everyday tasks– Strength for
“extraordinary” tasks
Strength Training
Recommendations (health-related)– Dynamic resistance exercises– Full range of motion– 8-10 different exercises– 8-12 repetitions per exercise– Weight that corresponds to 60 - 85% of 1RM– Large muscle groups first– Alternate muscle groups for rest– Progress with success
Flexibility
Normal joint Range of Motion (ROM)– Limited by bony structures– Limited by connective tissue– Limited by muscle tension
• “Re-set” tension / length
– Hyper mobility
Flexibility
Training to improve– Principles of exercise apply (O, S, R)– Corollary applies too (consistency)– Training variables apply (F, I, T)– Best done when muscles are “warm”– Best done - not to the point of pain– Best done slowly – static not ballistic
Body Composition
What makes up the body?– Water
• 99 out of every 100 molecules– Bone
• Skeletal, teeth– Protein
• Membranes, organs, muscle– Fat
• Membranes• Nervous tissue• Pericardial• Intramuscular• Intra-abdominal• Subcutaneous
Body Composition
Body fat– Stored carbons
Adipose cells– Increase volume to store carbons– Multiply when they reach a particular size
• @ ~ 60 lb fat increase• Do not “un-multiply”
Body Composition
Estimation vs. Measurement– Hydrostatic weighing– Skin fold calipers– Electrical impedance– Infrared absorbance– Dual X-ray Absorbtometry (DEXA)
Body Composition 144,000 bariatric surgeries expected in 2004—up from 16,200 in 1992 Severely obese are increasingly turning to this life-altering measure. Most lose weight quickly and continue to lose for up to two years. Also seeing improvements in almost all their obesity-related conditions. 1 in 100 who have gastric bypass dies 10 - 20 percent of all bariatric surgery patients require follow-up operations
to correct complications. Almost 30 percent develop nutritional deficiencies, including osteoporosis,
anemia, and metabolic bone disease. —Cate Lineberry - National Geographic
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