Transcript Physiological Adaptations to Training

Physiological Adaptations
to Training
HPHE 6310
Suzan Ayers, PhD
Western Michigan University
Chapter 11 Overview (Abernethy)
 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
Helpful Reminders
 ATP=adenosine
 High-energy
triphosphate
molecule that provides muscular energy
 PCr=phosphocreatine
 Major
 Lactic
fuel source at activity onset and for up to 30 sec
acid=by-product of anaerobic glycolysis
 Associated
with muscular fatigue
 Immediate
energy system (stored energy, high-energy
phosphagen, ATP-PCr system) 0-30s
 Anaerobic
180s
 Aerobic
glycolytic system (lactic acid system) 20-
or oxidative system >3 min
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
Management of/Planning for
Performance Limitations?
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 (or major contrib.
from anaerobic system)
 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
strength: 1RM
 Can

be increased 20-100% over several months
Age-appropriate strength training practices
 Muscular
 Force
power: strength x speed
and contraction speed inversely related
 Practical
examples from weight room observations
 Muscular endurance:
(can be ↑ by ↑ strength)
Repeated sub-max reps
 Wks
1 to ~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 (curvilinear relationship)
 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)
 This
is a super summary table
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)
 2-1-4 cadence based on this relationship
 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 not immediate, lactic acid-based soreness
 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
 ACSM


(2011): 150 mins/wk
30-60 mins x 5 d/wk of moderate PA
20-60 mins x 3 d/wk of vigorous PA
 ACSM (2008) for school-age children (6-17 yr):
 60+
mins/day (cumulative), MVPA
 Vigorous 3+ d/wk
 Variety, enjoyable, all fitness components
 Adults vs children
Chapter 12 Overview (Abernethy)
 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
Safety Guideline
“Lifting maximal weights
should be delayed until all the
long bones have finished
growing at about 17 years of
age (older in boys).”
(p. 109)
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
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)
Next Week
Skill analysis
-Video
-Task analysis development (template online)