What measurement is considered the best indicator of an individual's level of aerobic fitness
Why is VO2 considered the best indicator of aerobic fitness?
Dependent on: cardiac ouput, ventilatory capacity, circulation, ability of tissues to remove oxygen from the blood
what are limiting factors in determining VO2 max?
Healthy individual: max cardiac output; asthma chronic bronchitis, or ephysema: ventilatory compromise; Emphysema: abnormalities in the ventilation-perfusion ratio of the lungs; Peripheral vasular disease: decreased tissue perfusion
Define common indicators of physical fitness:
blood lactate threshold, ventilatory threshold
Are the VO2 max values the same in an individual performing various exercises? (treadmill, cycling, arm ergometer)
No; dependent on amount of muscle mass involved or specific exercise
What is oxygen deficient?
amount consumed and amount required for a particular exercise
What effect does warming up have on the oxygen deficit?
Decreases the deficit, by making it more accessible for the tissues
How do the resting stroke volume, heart rate, and cardiac output of a well-trained athlete compare with those of a sedentary individual?
An athelete has a larger resting stroke volume and a lower resting heart rate, but comparable cardiac output
UE vs LE exercise difference are caused mainly because of what?
vasodialtion in exercising muscles and vasoconstriction in nonexercising - UE = increased vasoconstriction leading to higher HR, BP, RR, and tot peripheral resistance; lower cardiac output and SV
What happens to systolic, diastolic, and mean arterial pressure during exercise?
Systolic and mean arterial pressure rise because of higher stroke volume. Diastolic remains constant or drops slightly because of a decrease in total peripheral resistance
Why is the arteriovenous oxygen difference larger in endurance athletes?
With exercise the density and size of the mitochondria increase which allow for more effective oxygen extraction, also capillary density increases allowing for more time for mitochondria to draw out oxygen.
Long term effects of endurance training on the heart and on blood volume?
increases blood volume, and slowly causes hypertrophy of the heart
Describe the contributions of stored ATP, creatine phosphate, glycolysis, and aerobic metabolism toward providing ATP during intense exercise over time?
Stored ATP: used primarily for maximal intensity exercise causing fatigue after about 4 seconds; Creatine phosphate: after exercise causing fatigue in 10s supplies energy to replenish ATP stores after about 6s; Intense exercise between 10s -2 min depends on anaerobic glycolysis; Instense exercise lasting longer than 2 min aerobic metabolism provides most of the ATP
What can be done to improve the system for providing ATP during intense training?
To improve the ability of creatine phosphate: several bouts of intense exercise lasting 5-10s with 30-60s rest; To improve anaerobic capacity, several bouts of intense exercise 1 min with 3-5 min recovery
Compare difference in size, velocity of contraction, fatigability, and metabolism among type I, type 2a, type 2b muscle fibers:
Type I (slow twitch): low velocity, good endurance, small diameter, aerobic metabolism; type 2a (intermediate twitch): intermediate velocity, average resistance to fatigue, intermediate diameter, type of metabolism aerobic and anaerobic; type 2b (fast twitch): velocity of shortening fast, endurance poor, diameter large, metabolism anaerobic
Which type of muscle fiber is activated during moderate intensity, long-duration exercise, such as jogging?
Type 1 (slow twitch)
Why are specific muscle fiber types activiated during different kinds of exercise?
size of the motor neuron (slow twitch have lower threshold of stimulation)
Explain why movements become less precise and refined as low-intensity exercise is continued for a prolonged period of time?
As slow twitch muscles fatigue and glycogen is depleted, fast twitch fibers are recruited which results in less control of movements.
Can the three muscle fiber types be changed as a result of exercise?
Type I: N, but they can improve their ability to use anaerobic metabolism. Type II: can improve their ability to use aerobic metabolism Type IIb: can convert to IIa fibers with endurance training.
What changes occur in muscle with endurance training?
Improved oxygen delivery and use = increased cross sectional area. Mitochondrial volume to contract protein volume decreases. Aerobic capacity decreases. Conversion of 2b to 2a fibers.
What causes improvements in strength with resistance training?
First 2 wks: 90% of change due to neural changes - recruitment pattern of motor units, increases in CNS activation, more synchronization of motor units, less neural inhibition After 6 wks: 90% of the improvements are from an increase in contractile proteins.
Well training man vs woman and VO2 max:
greater in men 10-20%, has increased ability to carry oxygen
What is the cause of athletic amenorrhea?
Woman who train heavily have increases: catecholamines, cortisol, and Beta-endorphines which inhibit release of luteinizing hormone and follicle stimulating = decreased estradiol. Additionally. physical and emotional stress, diet, and presence of menstrual irregularity contribute.
Is it true that pregnant women who are physically fit deliver more easily?
Physiological chnages that occur during pregnancy that affect exercise?
1.) After the first trimester the supine position results in relative obstruction of the venous return by enlarging the uterus and a decrease in cardiac output 2.) Stroke volume and cardiac output 3.) Exercise during pregnancy increases a greater degrees of hemoconcentration that does not include exercise in a non pregnant state 4.) 10-20% increase in oxygen consumption 5.) Increased work for breathing, decreased available oxygen 6.) Shift in the center of gravity 7.) Basal metabolic rate and heat production increase. 8.) 300 kcal per day required to meet metabolic needs 9.) Increased carb use
General Guidelines for exercise to increase aerobic fitness:
1.) performed 3-5x/wk 2.) Intensity should maintain HR 65-90% of max, except for unfit individuals 55-64% 3.) Duration 20-60 min continuous or 10 min intermittently through day 4.) large muscle groups with lower intensity exercise of longer duration. 5.) proper warm up and cool down
List general ACSM guideline for ex prg to increase muscular strength:
1.) progressive and individualized 2.) one set 8-10 exercises that conditions major muscle groups 2-3x/wk, multiple sets may provide greater benefits 3.) 8-12 reps, 10-15 for more frail individuals 4) heavier wts near max tension with few reps; muscular endurance lighter wts and more reps 5.) Upper body 65-70% vs 75-80% for lower body of max wt recommended to train with
ACSM guidelines for wt loss:
1.) combination of exercise and diet 2.) aerobic most effective 3.) 3 days/wk 30-45 min for the avg person ~250-300 kcal
ACSM guidelines to perserve bone health:
1.) WB'ing endurance activities 2.) moderate - high intensity in terms of bone loading forces 3.) WB'ing endurance activities should be 3-5x/wk resistance 2-3x/wk 4.) duration 30-60 min/day 5.) balance activities for older adults
How do exercise and training affect the endocrine system and the resting levels of hormones?
Most hormones increase, insulin decreases, thyroid do not change; Resting levels of ACTH, cortisol, catecholamines, insulin, and glucagons decrease with training which may be related to greater energy stores or decreased perception of stress.
Does exercise affect the prevalence of upper respiratory infections?
Moderate may decrease the prevalence, while heavy endurance activities will likely increase the prevalence 1-2 wks post activity i.e. a marathon
Does exercise lower resting BP in normal and hypertensive individuals?
Should pts with COPD exercise?
mild to moderate will likely benefit from ambulation; severe COPD it is questionable if exercise will benefit these patients.
Difference in heart rate change between normal and heart transplant?
Normal will adjust rapidly, heart transplant depends on circulation changes and the heart is denervated so the change is slow.
Difference in resting HR in norm vs heart transplant?
transplant = higher resting HR, there is no parasympathetic tone
thoracic level SCI are at risk for fainting s/p UE exercise because:
no sympathetic LE innervation of vasculature = lack of vasocontriction leading to venous pooling followed by syncope.
Most common problem associated with exercising in cold environments?
Overdressing, leading to hyperthermia
List strategies to avoid hypothermia and hyperthermia when exercising in the cold?
Dress in layers; stay dry - heat is lost more rapidly when you are wet
Describe physiological changes when exercising in the cold?
distal vasoconstriction, but head not effected and 25% of heat loss occurs in the head; shivering produces heat; strength power and VO2 max decrease with hypothermia
Possible reasons for decreased max strength and power with hypothermia?
increased viscosity of skeletal muscle, resistance to blood flow, and decreased maximal nerve conduction velocity
Two most common problems with exercising in hot environment?
dehydration and hyperthermia
Dehydration and hyperthermia are avoided by:
Pathological changes when exercising in a hot environment?
sweat production 2-3L/hr leading to dehydration. Core temp increase. Decrease in venous return, increases HR, decreased SV and cardiac output. Normally skin BF increases, but with dehydration it vasoconstricts to preserve volume; increased lactate concnetration
Does living at high altitude improve exercise tolerance at high altitude?