Ch 9 Physiology & Exercise

Chapter by Carol L Christensen

In Women In Sport

Notes by N. Bailey

Introduction to the Chapter

Chapter Focus:

physiological differences and similarities

& Other physiological concerns

Records Improving Performance records improving for

both men and women Women are closing the gap For both aerobic capacity & speed

events Much overlap between the sexes Look at data on page 180

Factors Affecting Performance Differences Hormonal differences ate menarche Socio-cultural differences: Clothing, activity level, lack of

opportunities for women, lower monetary rewards

Social myths: women are more easily injured, media coverage that marginalizes women athletes, gender roles

Physiology & Performance Pre-puberty and Puberty Aerobic Capacity Anaerobic Capacity or Power Muscle Strength and Physiology Body Composition

Puberty 12 yrs: Average age of puberty for girls Prior to that differences accounted for

by differential training and skills, not physiology

Boys mature 2 – 3 years later Mature male larger size due to

increased length of growth period

Aerobic Capacity Females at a disadvantage de to

smaller size (fewer rbc, lower hemoglobin concentration, smaller heart, lungs, and lower blood volume

15% to 25% disadvantage Performance records demonstrate that

this difference can be somewhat overcome with training and coaching

Anaerobic Capacity or Power

Women have less muscle mass And lower Anaerobic Power AnT Anaerobic threshold is related to

endurance performance. The point where anaerobic energy

sources are used at the cell site When lactic acid accumulates Women can’t maintain as fast a pace

Strength No differences in muscle tissue itself Differences in strength greater than

that for anaerobic and aerobic power Large overlap, but generally women

have 66% of the strength of men Upper body, 56% as strong as men Lower body, 72% as strong No Difference in fast and slow twitch

Body Composition Female athletes closer to male athlete

counterparts than to untrained women Average young woman 22 to 24%

body fat Average woman athlete 17 to 14% Average 60 yr- old woman professor ? Average untrained male: 14 – 16%

Response: Environment Conditions Temperature Regulation Hot Environments Cold Environments Altitude Air Pollution

Importance of Topic Various environments impose

demands on the body during exercise In extreme conditions all are affected With moderate changes some people

are affected and some are not Responders experience symptoms

with mild conditions v. Non-responders

Temperature Regulation Hyper- & hypothermia occurs in

extreme temps & are life threatening Exercise increases metabolism &

therefore, heat Okay in cold climate, a problem in hot Hot environment: sweat 90% heat loss

Temperature Mechanisms

Convection: wind blowing on body Conduction: contact with colder or

warmer surface Radiation: heat transfer through

electromagnetic waves Evaporation of sweat that we

mentioned in the last slide

Hot Environments Higher heart rate, higher sweat rate,

increased glucose use for energy, increased blood flow to the skin

Responses help maintain temperature Men & women with similar aerobic

fitness levels respond similarly to heat In extremes disadvantaged because of

greater surface area to gain heat

Safety Precautions Heat stroke, exhaustion & dehydration Drink plenty of fluids, especially water Reduce intensity, duration Avoid hottest part of the day Acclimatization: reduced sweat

rate,earlier onset, increase plasma volume takes about 14 days

Cold Environments Greater oxygen consumption during

sub-maximum work Increased glucose use for energy Less blood flow to the skin Hypothermia and frostbite Dress in layers, dry clothing, protect

the hands and the head

Different Responses? In general, similar physiological

responses Women at greater risk: greater surface

area relative to body mass helps cool Less muscle mass produces less heat With proper precautions both men and

women withstand cold temperatures

Altitude Low level of oxygen=hypoxia Higher heart rates, increased

ventilation, reduced aerobic power Endurance performance is impaired Adaptations: 4 to 6 months Increases in hematocrit, hemoglobin,

myoglobin and rbc attenuates hypoxia

Air Pollution At high levels: chest tightness,

difficulty deep breathing, eye irritation, headaches, dry throat

Endurance performance impaired by high carbon dioxide

Smog alerts: exercise indoors, avoid car exhaust

Men and women affected equally

Responses To Training Virtually the same for all individuals Altered by environmental conditions &

substances like drugs & alcohol Increases in heart rate, cardiac output,

ventilation, and metabolism

* When fitness levels are similar no sex differences

General Response Regular program of exercise results in

increased VO2 Max, strength, power and speed.

Type of training influences type of response – specificity principle

Training programs should be based on capacities, skills and abilities, not sex

Men will gain more than women

Specific Training Responses

Training depends upon particular stressors. For example:

Yoga for strength and flexibility Weight training for strength & loss of

body fat For Strength increase resistance For endurance increase reps

For Strength and Endurance

Lift 2 to 3 days per week Do at least one set of 8-12 repetitions Choose a weight that causes fatigue at

the end of the last repetition Better to underestimate the weight at

first in order to prevent muscle injury

Gender Differences Women’s earliest strength increase

result of increased muscle fiber recruitment

Men’s earliest increase due to increase in muscle fiber size

After several weeks of training women also experience hypertrophy

Anaerobic Training Interval training for 50 to 400 meter

runs Timing of the work and rest intervals

determines the specific training result For most running games require both

aerobic and anaerobic training Wind sprints= anaerobic + aerobic

training needed for running games

Stretching Never stretch a cold muscle Warm up by walking, jogging before

stretching Static stretch better than ballistic Stretch the muscle until slight tension

is felt, not pain. Hold for 15 to 60 seconds

No evidence of injury prevention

Warming Up & Cooling Down

Gradual adjustment to increase demands of exercise: oxygen delivered to muscle cells, decreased time for muscle contraction

Do low intensity activity similar in nature to the workout activity

Cool down – same activity only less intensity. Best time to stretch

Special Physiological Concerns

Menarche Menstruation Menopause Pregnancy Osteoporosis Injuries

Menarche Training at young age may delay onset

of puberty or maybe not Trained females begin menstruation

from .5 to 2.5 years later No evidence that delay is harmful in

any way Early maturing girls may drop out of

sport so we find these data

Menstruation Research results unclear about effects

on performance Individual variability obscures any

patterns of performance. Some evidence suggests that regular

exercise decreases incidence and severity of painful menstrual periods

Menstrual Disruption Higher incidence of menstrual

disruption in younger, highly motivated athletes, in intensively trained athletes, and in sports that emphasize lean body type

Amenorrhea related to osteoporosis Female Athletic Triad also a concern

Menopause A drop in circulating hormones,

especially estrogen Hot flashes not harmful Not much studied No difference in ability to improve

fitness levels Exercise recommended for fat control

& delay effects of aging

Pregnancy Increased blood volume, cardiac

output, fat and weight distribution, changes in most systems

No difference between athletes and non-athletes in major disorders

Athletes shorter periods of labor and fewer complications

Recent Research Exercising pregnant women have

higher ventilation volumes, higher ratings perceived exertion, energy expenditure

Don’t do maximum effort High risk pregnancy – avoid exercise Most benefit from exercise: 3days per

week; non-weight bearing

Osteoporosis 4 times more likely in women Three major risk factors: low estrogen,

low calcium, lack of physical activity Prevention should start in the teen

years ERT recommended Low impact exercises

Injuries In most activities no difference in injury

rates Anterior cruciate ligament injuries the

exception to this rule Difference in injury rate probably not

related to anatomy Prevention and rehabilitation methods

the same; get into “good shape”