Physiological Adaptations to Training Suzan Ayers, PhD Western Michigan University HPHE 6310.
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Transcript of Physiological Adaptations to Training Suzan Ayers, PhD Western Michigan University HPHE 6310.
Physiological Adaptations to
Training
Suzan Ayers, PhDWestern Michigan University
HPHE 6310
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
Chapter 11 Overview (Abernethy)
ATP=adenosine triphosphate High-energy molecule that provides muscular energy
PCr=phosphocreatine Major fuel source at activity onset and for up to 30
sec
Lactic acid=by-product of anaerobic glycolysis Associated with muscular fatigue
Helpful Reminders
Immediate energy system (stored energy, high-energy phosphagen, ATP-PCr system) 0-30s
Anaerobic glycolytic system (lactic acid system) 20-180s
Aerobic or oxidative system >3 min
Power and speed activities (< 1 min) Amount of ATP & PCr stored in muscles
Max exercise (30s – 2-3 mins) Lactic acid accumulation and disturbance of
the chemical/electrical gradient across cell membranes
Middle distance events (3-10 mins) Lactic acid accumulation, moderate glycogen
depletion, electrolyte distribution disturbance
Exercise Performance Limitations (p. 144)
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?
Table 11.1 (p. 145) Adaptations to strength and sprint training
Tables 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 influencing extent of VO2 max ↑
Initial fitness, genetics, age, type of training
Energy System Responsesto 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 strength: 1RM Can be increased 20-100% over several
months Age-appropriate strength training practices
Muscular power: strength x speed Force and contraction speed inversely related
Practical examples from weight room observations
Muscular endurance: Repeated sub-max reps (can be ↑ by ↑ strength)
Muscular Adaptations to Strength Training
Wks 1 to ~8=primarily neural adaptations
Hypertrophy begins after 6-8 weeks of training Max hypertrophy occurs when IIb fibers are recruited via [↑]
training
Metabolic 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
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
Training Principles
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
Min dose (average healthy young adult): To improve VO2 max: 15min @ 60% VO2,
3x/week To 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
Cardiovascular Endurance Training
Benefits of strength training Improved glucose tolerance, body
composition, blood lipids
Help prevent bone disorders
Maintain lean body mass, strength and mobility
Strength Training
Types of contractions Static, dynamic
Dynamic types: concentric (produce force) eccentric (stabilize or decelerate) 2-1-4 cadence based on this relationship
Types of resistance IM, IT (also isoinertial), IK
Improving strength/Hypertrophy Programs 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
Perform daily activities & reduce disease risk
Optimal/Minimal amounts vary by Individual goals Health status Fitness level Age
Health-Related Fitness Training
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
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
Chapter 12 Overview (Abernethy)
Children are NOT small adults
Aerobic capacity VO2 max much lower in children
Males tend to have higher VO2 max across lifespan
Endurance training can improve performance without notably changing VO2 max
Children’s Response to Exercise
Anaerobic capacity Much lower in children
Higher in males
Peaks: 14-16 yrs in females, ~20 yrs in males
Children recover faster after brief, [↑] exercise
Possibly due to < lactic acid production
Cardiorespiratory responses Blood flow to working muscles < in children
Children have < efficient respiratory systems: Higher respiratory rate Shallower breathing
Thermoregulatory responses Children 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 strength Similar 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)
Aerobic & anaerobic training VO2 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
Children’s Adaptations to Exercise Training
Strength training recommendations Closely supervise programs & spot lifts above
head
Emphasize form/technique and minimize competition
Focus on development of muscular endurance
High rep, low weight, min. 7-10 reps per set
No max lifts before 17 yrs of age
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
Exercise CapacityDuring Aging
Anaerobic capacity Peaks ~20 yrs of age
Older, 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 strength In 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)
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 pace may enhance enjoyment & compliance
Resistance training: 2-3x/week 8-10 exercises w/ all major muscle groups 8-15 reps/set
Exercise Prescriptionfor Older Adults
Table 12.2 (p. 176)
Lifespan Sex Differences in Response to Exercise
Skill analysis-Video-Task analysis development (template online)
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