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”