Transcript Maintaining Cardiovascular Fitness during Rehabilitation

Maintaining Aerobic
Capacity & Endurance
During Rehabilitation
Chapter 10
Why is it important to maintain
cardiorespiratory fitness?
 It is a critical component of any
rehabilitation, but is often the most
neglected
– Considerable amounts of time are spent
preparing for the demands of a season
• Time lost due to injury can result in considerable
cardiorespiratory decrements
 Cardiorespiratory Endurance
– Ability to perform whole-body activities for extended
periods of time without excessive fatigue
Training Effects on the
Cardiorespiratory System
 Cardiorespiratory activity is a coordinated
function of 4 components to transport O2
throughout body
–
–
–
–
Heart
Blood vessels
Blood
Lungs
 Improvements due to training
– Results in  capability of each of the above
elements
– Provides necessary oxygen (O2) to working
tissue
Adaptations of the Heart to Exercise
 Heart Rate (HR)
– With exercise, the
muscle’s use of 
O2 results in an 
need for O2
transport
– Heart work load
increases
proportionally to
intensity of
exercise
– Monitor HR =
indirect measure
of  consumption
 Stroke Volume
(SV)
– Volume of blood
being
pumped/beat
– Approximate
volume pumped =
70mL/beat
– Maximal volume =
40-50% of HRmax
• 110-120 beats/min.
• Above this point 
in volume being
pumped is related
to heart rate 
 Cardiac Output (Q) –
– Amount of blood heart pumps/minute
– Q = SV x HR
• Normal = 5L blood/min. @ rest
– Primary determinant of maximal O2 rate
consumption
– With exercise, Q  4x-6x of resting levels
(normal – endurance athlete)
– Training effect
•
•
•
•
Stroke volume  while exercise heart rate 
Heart efficiency
Heart hypertrophy w/ exercise
Females 5-10% higher Q than males (likely due to
lower concentration of hemoglobin in the female,
which is compensated for during exercise by an
increased cardiac output
 Adaptations in Blood Flow
– Blood flow is modified during exercise
• Flow to non-essential (exercise related) organs is
decreased
• Results in increased flow to working muscles
• Even though blood flow to heart increases – the
percentage of total cardiac output remains
unchanged
– Increase in blood vessels to musculature
– Total peripheral resistance decreases during
exercise
• Increase in vasodilation
 Blood Pressure (BP)
– Determined by cardiac output in relation to total
peripheral resistance to blood flow
– Systolic pressure - pressure created by heart
contraction (top number)
– Diastolic pressure - relaxation of heart (bottom
number)
– Systolic pressure  in proportion to O2
consumption & Q
– Consistent aerobic exercise will produce  in
overall resting BP levels
 Adaptations in the Blood
– Training for improved cardiovascular
function  total blood volume
– As a result of increased blood volume,
increased O2 carrying capacity increases
• Total available hemoglobin increases
– Overall hemoglobin concentration remains
the same or may slightly  with training
• Hemoglobin - O2 is transported throughout the
system; iron-containing protein that has the
capability of easily accepting or giving up
molecules of O2 as needed
 Adaptations of the Lungs
– Pulmonary function improves with training
– Volume of inspired air 
– Diffusion capacity of lungs 
• Enhances exchange of O2 and carbon dioxide
– Pulmonary resistance to air flow is also 
 Overall Effects of Training
–
–
–
–
–
–
–
–
 resting heart rate
 heart rate at specific workloads
 recovery time
 muscle glycogen use
Unchanged cardiac output
 stroke volume
 capillarization
 lung functional capacity
Maximal Aerobic Capacity
 Maximal oxygen consumption (VO2max)
– Volume of O2 consumed per body weight per
unit of time (ml/min/kg)
– Best indicator of cardiorespiratory endurance
– Average college athlete = 50-60 ml/min/kg
– World class endurance male athlete = 70-80
ml/min/kg
– World class endurance female athlete = 60-70
ml/min/kg
Rate of Oxygen Consumption
 Rate of O2 consumption is about the same for
all individuals, depending on fitness level per
activity
 Greater intensity = greater O2 consumption
 A person’s ability to perform activity is related to
amount of O2 required by that activity
– Ability is limited by the max. rate of O2
consumption the person is capable of delivering
into the lungs
 Fatigue occurs when:
– Insufficient O2 supplied to muscle
– Greater % of maximal O2 consumption during an
activity = less time activity can be performed
– Factors affecting maximal rate
• External respiration (involving ventilatory
process)
• Gas transport – accomplished by
cardiovascular system
• Internal respiration (use of O2 by cells to
produce energy)
• Most limiting factor is ability to transport O2
through system
– High maximal aerobic capacity indicates all
3 levels are working well
Maximal Aerobic Capacity:
Inherited Characteristic
 Genetically determined range
– Training allows athlete to obtain highest level
within that range
 Fast-Twitch vs. Slow-Twitch Muscle Fibers
– Range of VO2max is largely determined by
metabolic and functional capability of skeletal
muscle
– Higher % of fatigue resistant, endurance
oriented slow-twitch fibers will enable individual
to utilize more O2 and have higher VO2max
Cardiorespiratory Endurance and Work
Ability
 Cardiorespiratory
endurance is key
component in
individual ability to
perform daily
activities
 Fatigue & percent of
VO2max are closely
related for particular
workload (A vs. B)
 Training goal
– Increase ability of
cardiorespiratory
system to supply a
sufficient amount of
O2 to working
muscles
Producing Energy for Exercise
 Cellular Metabolism
– To Grow, Generate energy, Repair damaged
tissue, Eliminate waste
– Energy is produced from the breakdown of
nutrients resulting in formation of Adenosine
triphosphate (ATP) (primary energy store)
– ATP is produced in muscle tissue
• Glucose from blood or glycogen (muscle or liver) is
broken down to glucose & converted to ATP
– Glucose not needed immediately is stored as glycogen
in the resting muscle & liver; can be later converted back
• Fat and protein can be utilized to produce ATP
• Fat is utilized when glycogen stores become depleted
– Activity becomes more duration/endurance oriented
– Different activities have differing energy needs
and rely on different cellular processes
Aerobic vs. Anaerobic Metabolism
 Both systems generate ATP
– Initial ATP production from glucose occurs in
muscle (without O2 = anaerobic)
– Transition to glucose & fat oxidation (requiring
O2 = aerobic) to continue activity
 Generally both systems occur to a degree
simultaneously
 Type of ATP production relative to intensity
– Short burst (high intensity) = anaerobic
– Long duration (sustained intensity) = aerobic
 Excess Post-exercise Oxygen
Consumption (Oxygen Deficit)
– With  intensity, insufficient amounts of O2
are available which results in O2 deficit
– Occurs initially during activity (1st 2-3 min. of
exercise) – body adapts
• Hypothesized that it may be a result of initial lactic
acid production
– Deficit may be the result of disturbance in
mitochondrial function due to increased
temperature
Techniques for Maintaining
Cardiorespiratory Endurance
 Primary concern
– Nature of injury & techniques available as a
result of injury
– Upper vs. Lower extremity injury & options
– Match fitness
• Engagement of functional activities specific to
sport to maintain fitness
 Goal
– Maintain fitness levels
Continuous Training
 FITT Principle
–
–
–
–
Frequency
Intensity
Type (mode)
Time (duration)
 Frequency
– Competitive athlete should be prepared to
engage in fitness activity 6 times per week,
allowing 1 day for body repair and
maintenance
 Intensity
– Should be heart rate controlled &
monitored
• Goal is to plateau heart rate at desired level
– Monitor pulse
• Preferably radial pulse
• Should be engaged in workout for 2-3 minutes
prior to checking
– Workouts should be set as percentage of
heart rate max (60-90% ACSM recommendation)
• Appropriate estimate of HRmax = 220-Age
– Karvonen formula
• Target HR = HRrest + (0.6[HRmax-HRrest])
– Rate of Perceived Exertion (RPE)
• Scale (6-20) that can be used to rate exertion
level during activity
 Type of Exercise
– For continuous training activity must be
aerobic
• Easy to regulate intensity (speed up or slow
down)
• Intermittent exercise is too variable (speed and
intensity)
 Time (duration)
– Minimal improvements = exercise for 20
minutes
– ACSM recommends 20-60 minutes with HR
elevated to training levels
– Greater duration = greater improvements
Interval training
 Intermittent activities involving periods of intense work &
active recovery
 Must occur at 60-80% of maximal heart rate
 Allows for higher intensity training at short intervals over
an extended period of time
 Most anaerobic sports require short burst which can be
mimicked through interval training
 HR may reach 85-95% of maximum at peak and 35-45%
during rest
 Should be combined with continuous training
Fartlek Training
 Cross-country running that originated in Sweden
 Speed play
– Similar to interval training in the fact activity occurs over a
specific period of time but pace and speed are not
specified
– Puts surges into workout, varying length of surges to
specific needs
– Consists of varied terrain which incorporates varying
degrees of hills
 Dynamic form of training – less regimented
 Must elevate heart rate to minimal levels to be
effective
 Popular form of training in off-season
Par Cours
 Combination of continuous & circuit
training
 Jogging short distances, from station to
station, & performing a designated
exercise
 Gain aerobic fitness while performing
calisthenics
 Found typically in recreational parks