Transcript Physiological Adaptations to Training

Physiological Adaptations
to Training
HPER 6310
Dr. Suzan Ayers
Western Michigan University
Lecture Overview
 Exercise
Performance Limitations
 Energy System Responses to Training
 Muscular Adaptations to Strength Training
 Training Principles
 Cardiovascular Endurance Training
 Strength Training
 Health-related Fitness Training
Purpose of exercise training:
To induce metabolic & structural adaptations to delay fatigue
Exercise Performance
Limitations (p. 144)
 Power
and speed activities (< 1 min)
 Amount
 Max
of ATP & PCr stored in muscles
exercise (30s – 2-3 mins)
 Lactic
acid accumulation and disturbance of the
chemical/electrical gradient across cell membranes
 Middle
 Lactic
distance events (3-10 mins)
acid accumulation, moderate glycogen
depletion, electrolyte distribution disturbance
 Longer
events (10-40 mins)
 Moderate
lactic acid accumulation, partial glycogen
depletion, dehydration, chemical/electrical gradient
disturbance
 Very
long events (>40 mins)
 Glycogen
depletion, dehydration, ↑ body
temperature, ↓ glucose levels, Δ in ratios of amino
acids in blood
Energy System Responses
to Training
 Table
11.1 (p. 145)
 Adaptations
 Tables
to strength and sprint training
11.2 (p. 146) and 11.3 (p. 147)
 Adaptations
to endurance training
 ↑capacity for oxidative metabolism = < lactic acid
 Only endurance training will ↑ oxidative capacity
 Only [↑] speed or power training will ↑
intramuscular stores of PCr and ATP
 Factors
 Initial
influencing extent of VO2 max ↑
fitness, genetics, age, type of training
 Lactate
threshold
 [Exercise]
below which one can, theoretically, ↔
exercise indefinitely w/o fatigue
 Below this point, ATP produced w/o ↑ lactic acid
build-up
 Trained: 70-85% VO2 max
 Untrained: 50-65% VO2 max
 [Exercise] or pace associated w/lactate threshold
better predictor of elite performance than VO2 max
Muscular Adaptations to
Strength Training
 Muscular
 Can
strength: 1RM
be increased 20-100% over several months
 Muscular
 Force
power: strength x speed
and contraction speed inversely related
 Muscular endurance:
(can be ↑ by ↑ strength)
Repeated sub-max reps
 Wks
6-8=primarily neural adaptations
 Hypertrophy

Max hypertrophy occurs when IIb fibers are recruited via [↑] training
 Metabolic



begins after 6-8 weeks of training
adaptations (from intense strength training):
↑ in intramuscular stores of ATP, PCr and glycogen in FT fibers
Results in more and faster provision of ATP, PCr
Final outcome: more force possible in brief, max contractions
Training Principles
 FITT:
Frequency, intensity, time, type
 Specificity: training must reflect activity’s
demands
 Overload/Progression: progressive ↑ in
training loads (do > body typically does)
 Individualization: personalize program
 Reversibility/Regularity: ‘use it or lose it’



Adaptations continue as long as demands exist
↔ requires much less effort than initial adaptations
Detraining begins within days of stopping training
 Periodization:
cyclical training designed to help
athletes peak at desired time
 Often
related to season (pre-, in-, post-)
 Helps prevent boredom, injury, overtraining
 Overtraining
 Leads
to prolonged fatigue, frequent illness, poor
performance
 Often due to ↑ training volume or intensity too fast
w/o adequate recovery between sessions
 Continuous
Training: exercise w/o breaks
 Table
11.4 (p. 154)
 Constant or varied pace
 Differences between [higher]/[lower] adds variety
 Interval
Training: Alternating periods of
exercise and rest
 Table
11.5 (p. 155)
 Remember
how much I love tables
Cardiovascular Endurance
Training
 Min
 To
 To
dose (average healthy young adult):
improve VO2 max: 15min @ 60% VO2, 3x/week
improve fitness
 20-60min
@ 50-85% VO2, 3-5x/week
 Endurance
athletes should approximate
intensity and duration of competition
 Health benefits occur w/o ↑ changes in fitness

Loss of body mass, ↓ blood pressure, ↓ risk of heart disease
Strength Training
 Benefits
of strength training
 Improved
glucose tolerance, body composition,
blood lipids
 Help prevent bone disorders
 Maintain lean body mass, strength and mobility
 Types
of contractions
 Static,
dynamic
 Dynamic
types:
 concentric
(produce force)
 eccentric (stabilize or decelerate)
 Types
 IM,
of resistance
IT (also isoinertial), IK
 Improving
 Programs
strength/Hypertrophy
must be specific to goals
 Reps, sets, training volume (reps x sets), intensity
 1RM, 10RM
 [Moderate-to-high], high volume for several weeks
 Power: hypertrophy first then speed development
 Table 11.6 (p. 158); relationships among rest/goals
 DOMS
 24
hrs to 1-2 weeks in duration
 More
intense when eccentric training used
 Specific
inoculation effect
 Correlated
with:
 Sub-microscopic
muscle damage
 Edema
 Leakage
of enzymes (creatine kinase)
 Inflammation
 Diminished strength
Health-Related Fitness
Training
 Perform
daily activities & reduce disease risk
 Optimal/Minimal
 Individual
goals
 Health status
 Fitness level
 Age
amounts vary by
 Surgeon
General (1996), ACSM (2000), Strong et
al. (2005) recommendations:
 30+
mins most days/week (cumulative), moderate
 Variety,
 Adults
enjoyable, all fitness components
vs children
Physiological Capacity and
Performance Across the
Lifespan
 Children’s
Response to Exercise
 Children’s
Adaptations to Exercise Training
 Exercise
Capacity During Aging
 Exercise
Prescription for Older Adults
 Lifespan
Sex Differences in Response to Exercise
Children’s Response to Exercise
 Children
 Aerobic
 VO2
are NOT small adults
capacity
max much lower in children
 Males
tend to have higher VO2 max across lifespan
 Endurance
training can improve performance
without notably changing VO2 max
 Anaerobic
 Much
lower in children
 Higher
 Peaks:
capacity
in males
14-16 yrs in females, ~20 yrs in males
 Children
recover faster after brief, [↑] exercise
 Possibly
due to < lactic acid production
 Cardiorespiratory
 Blood
responses
flow to working muscles < in children
 Children
 Higher
have < efficient respiratory systems:
respiratory rate
 Shallower breathing
 Thermoregulatory
 Children
responses
are < tolerant of prolonged exercise
 Children
lose > metabolic heat during exercise
 Children
sweat @ higher relative work rate
 Children
sweat < during exercise
 Children
have a < responsive thirst mechanism
 Muscular
 Similar
strength
between genders up to age 8-9 yrs
 Boys’ MS ↑ linearly to age 13-14 then accelerates
during adolescence
 Girls’ MS ↑ linearly to age 14-16 then flattens
 Body size, somatotype & MS more closely related in
boys than girls
 Simultaneous maturation of neural pathways cause
MS gains in boys & girls during/after puberty
Children’s Adaptations to
Exercise Training
 Aerobic
 VO2
& anaerobic training
max potential ↑ only 5-25% (vs 20-40% in adults)
↓
resting heart rate
↑
max cardiac output & stroke volume
↑
work rate @ lactate threshold
↑
max minute ventilation
 Strength
training recommendations
 Closely
supervise programs & spot lifts above head
 Emphasize
 Focus
on development of muscular endurance
 High
 No
form/technique and minimize competition
rep, low weight, min. 7-10 reps per set
max lifts before 17 yrs of age
 Children’s
 Strong
exercise prescription
et al. (2005)
 60+
mins/day MVPA that is developmentally
appropriate, enjoyable, & involve a variety of activities
 Exercise
 Prefer
for fun, peer recognition, social interaction
interval-type exercise in the context of
recreation and games
Exercise Capacity
During Aging
 Aerobic
↓
capacity
work capacity after age 30 may be due more to
sedentary lifestyle than solely to aging
 Continued training can slow the rate of decline
 Sedentary people’s ↓ VO2 max generally correlated
with changes in body comp
 ~50% of ↓ VO2 max due to ↓ in max heart rate
 Ability of skeletal muscle to extract/use oxygen
during exercise ↓ w/ age in the sedentary
 Oxidative capacity of skeletal muscle ↓ w/ age
 Anaerobic
 Peaks
 Older,
capacity
~20 yrs of age
sedentary folks show 6% ↓ per decade
 Closely
related to loss of muscle mass
 Anaerobic
capacity & muscle size ↓ w/ age more in
women than in men
 Muscular
 In
strength
untrained, MS peaks early 20s
 Aging,
sedentary folks show 2-4% ↓ per year
 Lean
body mass ↓ gradually from 30-50 yrs then
accelerates
 Atrophy
of larger, stronger FT muscle fibers
 Amt of connective tissue may ↑ while fiber size ↓
 Age-related changes in neural input (loss of FT fibers)
Exercise Prescription
for Older Adults
 Table
12.1 (p 175)
 Goal
of PA: ↑ / ↔ functional capacity, MS/ME,
quality of life slow/prevent onset of disease
 Low
to moderate [exercise] confers health benefits
 Self-selected
 Resistance
pace may enhance enjoyment & compliance
training:
 2-3x/week
 8-10
exercises w/ all major muscle groups
 8-15 reps/set
Lifespan Sex Differences in
Response to Exercise
 Table
12.2 (p 176)