Ch 9 Physiology Exercise

1. Ch 9 Physiology & Exercise Chapter by Carol L Christensen In Women In Sport Notes by N. Bailey

2. Introduction to the Chapter Chapter Focus: physiological differences and similarities & Other physiological concerns

3. 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

4. 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

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

6. 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

7. 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

8. 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

9. 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

10. 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%

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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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

18. 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

19. 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

20. 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

21. 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

22. 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

23. 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

24. 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

25. 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

26. 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

27. 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

28. 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

29. Special Physiological Concerns Menarche Menstruation Menopause Pregnancy Osteoporosis Injuries

30. 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

31. 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

32. 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

33. 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

34. 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

35. 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

36. 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

37. 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�