Essentials of Exercise- Chapter 5
Terms in this set (67)
what 2 major adjustments in blood flow must occur to meet the increased demands of muscle during exercise
an increase in cardiac output and a redistribution of blood from inactive organs to the active skeletal muscle
sinatrial (SA) node vs. atrioventricular (AV) node
the SA node is located in the posterior wall of the right atrium and intrinsically controls the regulation of heart rate; the AV node is located on the floor of the right atrium and gives off many branches that facilitate vetricular contraction
chronotropic response vs. inotropic response
a chronotropic response is an increase in heart rate; an inotropic response is an increase in the force of heart contractility
VT1 vs. VT2
VT1 occurs at ~the first time that lactate begins to accumulate in the blood, and represents hyperventilation relative to VO2; VT2 occurs at the point where lactate is rapidly increasing with intensity, and represents hyperventilation even relative to the extra CO2 that is being produced
heat acclimation vs. heat acclimatization
heat acclimation is the relatively rapid process of physiological adaptation to exercise in the heat (several days or weeks); heat acclimatization is more gradual in onset and occurs in people who live in hot environments for months or years
twitch vs. summation
a twitch is a motor unit's smallest contractile response to a single electrical stimulation; summation is a series of multiple stimuli in rapid sequence, prior to relaxation from the first stimulus (this results in greater force production)
fiber hypertrophy vs. fiber hyperplasia
fiber hypertrophy is an increase in the size of existing muscle fibers; fiber hyperplasia is an increase the number of muscle fibers
why is systolic blood pressure affected more by exercise than diastolic blood pressure?
increased heart contractility and stoke volume increase the force with which blood leaves the heart; muscle action requires greater force or pressure to deliver bllod into the exercising muscles; vasodilation within the exercising muscles allows more blood to drain from the arteries
how does the redistribution of blood during exercise affect the skeletal muscle?
blood flow to the skeletal muscles increases from 10-15% at rest to 80-85% at maximal exercise
how does the redistribution of blood during exercise affect the brain?
during intense physical activity, the % of total cardiac output to the brain is decreased compared to resting, but the absolute volume of blood that reaches the brain is slightly increased due to the elevated cardiac output
how does the redistribution of blood during exercise affect the heart?
the % of total cardiac output that the heart receives in its coronary circulation is the same at rest and during maximal exercise, even though total coronary blood flow is increased du to the increase in cardiac output during intense exercise
how does the redistribution of blood during exercise affect the kidney and gastrointestinal tract?
blood flow to the kidneys and gastrointestinal tract diminishes, but does not cease
how does the redistribution of blood during exercise affect the skin?
blood flow to the skin increases as exercise intensity increases, but at maximal intensities it decreases
1 of the 2 fast acting hormones that exert widespread effects on the organ systems that are critical for exercise performance; triggers the "fight or flight response"
fast acting hormone that reduces blood glucose levels and promotes the uptake of glucose, fats, and amino acids into cells for storage
fast acting hormone that stimulates an almost instantaneous release of glucose from the liver and is part of a negative feedback loop in which low blood glucose levels stimulate its release
slow-acting hormone that stimulates free fatty acid mobilization from adipose tissue, mobilizes glucose synthesis in the liver, and decreases the rate of glucose utilization by the cells
slow-acting hormone that plays a major role in protein synthesis and decreases glucose uptake by the tissues, increases free fatty acid mobilization, and enhances gluconeogenesis in the liver
carbohydrate as fuel during exercise
major food fuel for the betabolic production of ATP, only macronutrient whose stored energy generates ATP anaerobically, crucial during maximal exercise that requires rapid energy release above levels supplied by aerobic metabolism
fat as fuel during exercise
role as an energy source is mainly determined by its availability to the muscle cell, mainly stored in the form of triglycerides and adipocytes
protein as fuel during exercise
must be broken down into amino acids before being used as fuel, use increases slightly during prolonged exercise lasting more than 2 hours, plays the smaller role of the 3 macronutrients in terms of fuel during exercise
phosphagen energy systen
used to meet immediate energy needs at the onset of exercise or with any increase in activity, has a very rapid rate of ATP production
aerobic energy systen
takes over as the predominant energy path way during endurance activities after the other 2 systems fatigue, has an unkimited system caoacity, has a slow rate of oxygen production
anaerobic glycolysis energy system
used during endurance activities orior to the body achieving homeostasis, or during activities when the intensity approaches the anaerobic threshold
4 mechanisms the body uses to give off heat during exercise
radiation, conduction, convection, evaporation
heat loss in the form of infrared rays, which involves the transfer of heat from the surface of one object to another without any ohysical contact (the sun's rays)
the transfer of heat from the body into the molecules of cooler objects that come in contact with its surface (warming up a seat)
a form of conduction wherein heat is transferred to either air or water molecules in contact with the body (wind from a fan replacing warm molecules with cooler ones)
occurs when heat is transferred from the body to water on the surface of the skin (sweating). When this water is accumulates sufficient heat, it is converted to a gas, removing heat from the body as it vaporizes
95 degrees F with 40% humidity
heat cramps or heat exhaustion possible
85 degrees F with 50% humidity
no risks involved
30 degrees F with calm winds
little danger for a properly clothed person
10 degrees F with 10 mph winds
danger for freezing of exposed flesh
why do women tend to sweat less than men and start to sweat at higher skin and core temperatures? How does this difference affect heat tolerance during exercise?
women have more surface area for their body weight, so they rely more on conduction, convection, and radiaton to regulate body temperature than do men, who generate greater quantities of heat (due to increased lean mass).
how long after the intiation of an exercise program can an increase in plasma volume be observed?
within one hour of recovery from the first exercise session
what is the physical performance advantage of reduced blood viscosity?
reduced blood viscosity enhances oxygen delivery to the active skeletal muscles because the blood flows more easily through the capillaries
why is the left ventricle the cardiac structure most affected by endurance training?
the left ventricle is responsible for the forceful propulsion of oxygenated blood through the arterial system
how does regular endurance training create more cross-sectional area for exchange between the vascular system and the active muscle fibers?
new capillaries develop in trained muscles to allow blood to more effectively perfuse the active tissues
why is the increase in size and numbe rof mitochondriawithin the skeletal muscles an important adaptation to long-term exercise?
since the mitchondria improve the muscle's capacity to produce ATP, increases in mitochondrial size and number enhance the muscle's ability to use oxygen and produce ATP via oxidation
why is an increase in rate coding due to resistance training so important to overall performance?
an increase in rate coding results in an increase in the frequency of discharge of the motor units and allows for a faster time to peak force production for the trained muscle
epinephrine and norepinephrine response to endurance training
decreased secretion at rest and at the same absolute exercise intensity after training
cortisol response to endurance training
slight elevation during exercise
insulin response to endurance training
increased sensitivity, normal decrease during exercise greatly reduced with training
glucagon response to endurance training
smaller increase in glucose levels during exercise at absolute and relative workloads
growth hormone response to endurance training
no effect on resting values, less dramatic rise during exercise
shock or alarm phase of the general adaptation syndrome
strength gains are attributed to neuromuscular adaptation only; involves cortisol secretion
adaptation phase of the general adaptation syndrome
characterized by progressive increases in muscle size and strength; represents major muscular adaptations
exhaustion phase of the general adaptation syndrome
repairs are inadequate and sickness or death occurs; can indicate a lack of adherence
primary signs and symptoms of overtraining
decline in physical performance with continued training; elevated HR and blood lactate levels at a fixed submaximal work rate; change in appetite; weight loss; sleep disturbances; multiple colds or sore throats; irritability, restlessness, excitability, and/or anxiousness; loss of motivation and vigor; lack of mental concentration and focus; lack of appreciation for things that are normally enjoyable
explains the outcome of a given type of training program such that the exercise response is specific to the mode and intensity of training
refers to strategically applying increased load on a tissue or system above and beyond the point at which that tissue or system is normally loaded
refers to the systematic process of applying overload
suggests that the rate of fitness improvement diminishes over time as fintess approaches its ultimate genetic potential
pertains to the losses in function experienced after the cessation of a training program
during cardiorespiratory exercise at higher intensities, what results in the greatest change percentage of total-body blood flow regulation?
increased blood flow to the working muscles
what increases after catecholamines are released from the adrenal medulla?
strength of contraction in the cardiac muscle cells
during exercise, what hormone causes increases in the production and release of liver glycogen and the availability of free fatty acids in the blood?
"hitting the wall" during an endurance event is primarily associated with _____.
severe glycogen depletion
what mechanism is primarily responsible for thermoregulation during exercise?
according to the National Athletic Trainers' Association, about how much fluid should a participant consume after a 60-minute cardiorespiratory workout?
450-675 mL (16-24 oz) for every 0.5 kg (1 lb) lost during exercise
the increased oxygen extraction at the tissue level resulting from long-term cardiorespiratory training is attributed least to an increase in ____.
what program modification would be most appropriate for a client who has an elevated resting heart rate, has recently lost 5 lbs, and seems distracted and lacking motivation?
decreasing exercise intensity and volume for several weeks to help him recover, as he appears to be overtrained
a training program for a hiking trip; consisting of strengthening exercises for the hip flexors and extensors, knee extensors, ankle plantarflexors, spinal stabilizers, as well as cardio training; is most representative of what training principal?
contracting the hip flexors during a supine hamstring stretch is an example of what stretching principle?
active isolated stretching
instead of holding stretches for 15-30 seconds at a point of resistance, stretches are held no more than 2 seconds, with each subsequent movement exceeding the resistance point by a few degrees (originally used during rehabilitation for surgery patients)
proprioceptive neuromuscular facilitation
capitalizes on the principles of autogenic inhibition and reciprocal inhibition; 3 basic types of PNF (hold-relax, contract-relax, and hold relax with agonist contraction)
states that activation of a GTO inhibits a muscle spindle response