Flashcards
PHYL2730 EXAM NOTES
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- 1Contribution of Energy Systems30s - 80% anaerobic, 20% aerobic
60-90s- 45% anaerobic, 55% aerobic
120-190s - 30% anaerobic, 70% aerobic - 2PCr & ATP Between Fibre Types- no diff in resting ATP concentrations
- 3x more PCr than ATP stores at rest
-5-15% more PCr stored in TIIB fibres than TI
-aerobic contributions in sprint vary 10-30% in people - 3Possible Causes of FatigueSubstrate depletion: ATP, PCR, glycogen, glucose
Metabolic by-products: Mg2+, H+, ADP, NH3, Pi, La-, free radicals, heat
-Lactic Acid Production: within exercising muscle high during intense sprint - 4How does Lactic Acid cause Fatigue-LA produced in muscle, dissociates to lactate ion and H+
-H+ accumulates in cell causing acidosis (decreases pH) - 5Buffering Proteins-Cell has proteins that 'buffer' against accumulating H+
-Recuce rate pH falls, slowing rate of fatigue
-H+ accumulation interferes w/ glycolytic pathway
-Acidosis impair activity of glycolytic enzyme PFK - less energy available for resynthesis - 6Enzyme Systems causing Fatigue-ATPases that act as pumps in muscle
- Ca2+ ATPase
-NA+-K+-ATPase - 7Sarcoplasmic Reticulum and Calcium Homeostasis-Low CA2+ATPase activity->reduced CA re-uptake
-Reduced CA re-uptake cause incomplete relaxation between contractions
-Pi released from PCr breakdown in sprint, binds to CA in sarcoplasmic reticulum and reduce net CA release - 8Na-K ATPase role in Fatigue-In repetitive tasks K lost from muscle cell and intracellular Na increases
-NA-K ATPase fail to operate at high enough rate to restore ionic gradient - 9What makes a good sprinter?-Higher P output due to genetics & training
-More TII fibres
-Greater hypertrophy of existing muscles
-Better synchronisation of motor-units
-High PFK activity (no change resting ATP or CrP with training) - 10How does change in buffering capacity affect athlete?-Higher intramuscular buffering capacity (through protein) than an endurance athlete
-Ability to neutralise protons delays onset of fatigue -> sprinter better at translocating protons out of active muscle cell - 11Sprint training causes an increase in...-CS & PFK activities
-VO2 Max
-30s sprint performance
-Sprinters have higher post-exercise blood L conc/n ->due to training-induced adaptations to the glycolytic pathway
-NO CHANGE fibre compotition - 12What is High Intensity Interval Training (HIIT)?Repeated sessions of brief, intermittent exercise, performed with an "all out" effort or at an intensity close to that which elicest peak oxygen uptake (>90% VO2 Peak)
- 13Effects of HIIT?-HIT sever wks improves aerobic evergy metabolism (maximal aerobic capacity & max. activities of mitochondrial enzymes)
-6xHIT in 2 wks increase oxidative capacity in skeletal muscle and improve performance during tasks that rely on aerobic energy metabolism - 14Why is HIIT important?-Resynthesis of PCr in muscle is aerobic process; improvements in aerobic fitness will allow faster PCr recovery
-Removal LA (restoration of normal pH) is aerobic process
-So, multiple sprint training improves anaerobic and aerobic capacity - 15Fibre Type distribution between different liftersBody Builders: highest T1 % and area
Powerlifters: higher TII % and area
Weightlifters: TII % and area greatest - 16Can fibre types change with training?-Cannot change between TI and TII
-Movement from TIIa<->TIIb is possible with training, TIIb-TIIa more common - 17What is stretch-induced hypertrophy?-Immobilisation of skeletal muscle in shortened and lengthened positions resulting in rapid loss & addition of sarcomeres
-16 workouts necessary to produce significant hypertrophic changes - 18What are the early adaptations to resistance training?-Neural: skill, reduced inhibition, improved synchronisation
-Strength paralleled by changes in EMG
-Later changes in strength are not matched by changes in EMG (& are therefore myogenic changes) - 19How does strength training affect neural adaptations?-Involves recruitment of high threshold motor units not previously recruitable and an increased firing rate of motor units
- 20How does strength training affect agonist muscles?-Agonist muscles make greater contribution to movement & there is reduced co-contraction of antagonists
-Co-contraction of antagonists provide joint stability and improve movement coordination
-Antagonist movement most common in high velocity movements where precision & braking's required - 21What does the combination of sprint and endurance training cause?-Adding strength to endurance: endurance does not improve
-Endurance added to strength: studies have shown strength gains are impaired - 22What are the reasons why concurrent strength and endurance training is not successful?-Fatigue reduce quality of training & impair rate of adaptation
-Fibre types->endurance training leads to adaptations to TI and increase in mitochondrial density. Mitochondria may occupy to space which would otherwise be taken up by contractile proteins (body builders vs. powerlifters) - 23Why does upper body strength decrease with endurance running?-Release of catabolic hormones in response to fall in blood glucose during endurance work; non-active muscle proteins may be catabolised for gluconeogenesis
- 24Unaccustomed eccentric exercise results in:-Loss of strength
-Reduction in ROM
-Muscle soreness
-Elevated plasma CK activity
-Limb swelling - 25What is Delayed Onset Muscle Soreness (DOMS)?-Muscle soreness late in exercise bout & immediate recovery period
-12-48hrs after exercise
-Occurs w/ eccentric muscle action
-Causes: structural damage to muscle cells & inflammatory reactions within muscles
-Maximises resistance training response - 26What is the 'Repeat-Bout' Effect?-1st bout of eccentric exercise = damage
-2nd bout (within several weeks) = less damage
-Protection may last 6-12 months - 27Isotonic Resistance Training-Isotonic contractions involve muscle contraction against a moveable load
-Muscle does NOT exert constant tension throughout ROM
-Tension varies with mechanical advantage - 28Isometric Resistance Training-Isometric contractions involve contraction a muscle at a fixed angle against an immoveable object e.g. wall
-Questionable specificity to most sports - 29Isokinetic Resistance Training-Isokinetic contractions invole muscles contracting throughout the movement at a constant speed
-Used in rehabilitation
-Expensive and speed specific
-NOT sport specific - 30What is the purpose of periodisation of strength?-Change in training volume & intensity over the course of the year/season
-Rest or reduced training periods/provides variety
-Allow for peak at right time, e.g. athlete periodising over 4yrs for Olympics - 31Performance differences for female athlete-Body composition: higher fat mass
-Physiological responses: higher % muscle mass in lower body 60%, same CSA
-Fibre Type distribution: fibre CSA less but distribution similar - 32Cardiorespiratory differences in females vs. males-VO2 Max 20% lower
-SV decrease, blood volume decrease due to lower haemoglobin levels
-Substantial overlap in untrained males and females - 33What is the female phenomenon 'energy deficit'?-Energy availability is primary cause of menstrual irregularities
-Energy availability falls below 30%, menstruation will cease (30kcal/kg/FFM/day)
-Amenorrheic athlete reduces her training and increase caloric intake by 10-20%, normal menses returns - 34How do menstrual disturbances occur?-Long-term energy restriction leads to endocrine disturbances -> disruption to the hypothalamic pituitary axis -> oestrogen release is reduced
-Low oestrogen levels reduce bone formation; bone becomes more sensitive to parathyroid hormone which promotes loss of calcium. - 35What is Anorexia Athletica?-Exhibit signs of anorexia or bulimia
-Excessive fear of becoming obese
-Restriction of caloric intake
-Weight loss (>5%)
-Associated with menstrual dysfunction
-May use binge eating & purging - 36How does anaerobic capacity differ in a young athlete?-Capacity reduced
-Decreased glycolytic capacity so produce less LA, less PFK
-Recover quicker - 37How Does Thermoregulation Differ in the Young Athlete-Decreased sweat rate: reliance on convection and radiation
-Increased SA/m: more gain in hot and loss in cold environments
-Slower rate of heat acclimitisation: increased risk of heat-related illness - 38What Training Adaptations occur in the Young Athlete?-Body composition
-Training can alter deposition of muscle, fat and bone
-Training has biggest difference in relative fat mass at 14 yrs - 39What are the expected benefits of resistance training in prepubescents?-13-3-% improvement in strength
-Similar in boys and girls
-2x/wk is sufficient
-Factors responsible: Improved motor skill coodination, improved motor unit activation - 40ACSM suggestions for resistance programs for young athletes-1-3 sets of 8-10 exercises: 6-15 reps
-1-2 mins between sets, 2-3x/wk
-begin 1 set of several upper and lower body exercises
-emphasis on proper technique & safety
-program variation: rubber tubing, weight machines, calisthenics - 41What are the basic principles for aerobic training in young athletes?-Large muscular activity resulting in accumulation of 30-60min/day
-Allow to be naturally active
-Allow to control intensity and duration
-Included in activities that develop basic motor and sport skill
-Weight-bearing for bone aquisition - 42What physiological characteristics come with ageing?-Increased adiposity (fat mass)
-Reduced muscle mass (sarcopenia)
-Reduced strength (i.e. grip strength)
-Reduced aerobic capacity
-Reduced BMD - 43How does diet effect the muscle?-Low protein diets lead to loss in muscle mass & function
-Protein intakes of at least 1g/kgBW/day more appropriate
-Digestive system impaired with age - 44How does age affect hormones and muscle mass?-Decrease growth hormone (GH)
-Decrease testosterone & oestrogen
-Oestrogen: levels decline drastically at menopause or amenorrhea
-Causes decrease in muscle mass - 45What are the consequences of sarcopenia?-Basal Metabolic Rate (BMR) decreases 15% between 30-80
-Decrease BMD
-Decrease Aerobic capacity
-Decrease functional capacity: walking, stair climbing - 46How does cardio respiratory fitness change with age?-Cardiorespiratory endurance declines with age
- ~1% each year
-Training before peak (25yrs) is beneficial, creates greater buffer - 47How & why should resistance training be implemented for older adults?-Older adults respond quickly to resistance training; 3x/wk w/ 1x high velocity
-Resistance training shown to increase plasma HDL concentrations
-Advantages are independent of gains in strength and muscle mass - 48Does protein intake with resistance training affect older adults?-Protein intake immediately following resistance training with older adults results in greater muscle growth
-This 'window of opportunity' is particularly important for elderly
-Older muscle more nutrient resistant and exercise help with nutrient uptake - 49Characteristics of exercise to benefit bone health-Site specific
-Weight-bearing or resistance in nature
-Dynamic & varied - 50Exercise goals for osteoporosis-Improve muscle strength & endurance
-Improve balance and stability
-Maintain/enhance mobility & quality of life
-AVOID: resisted, repeated or sustained trunk flexion, resisted abduction or adduction of leg, high impact aerobics - 51What are the 6 classes of nutrients?-Carbohydrate
-Fat
-Protein
-Vitamins
-Minerals
-Water - 52What are the nutritional factors associated with exercise-induced fatigue?-Glycogen depletion
-Hypoglycemia
-'Central' fatigue
-Dehydration
-Hyponatraemia (low blood sodium) - 53Why is dietary carbohydrate essential for athletes?-Muscle glycogen is unique fuel, used both aerobically and anaerobically
-Fat can only be used with oxygen - 54How many carbohydrates should athletes consume?-To maintain glycogen stores, CHO should be 50% of total calories/day
-Those in heavy training and engage in endurance exercise should consume 55-60%
-e.g. 3000 cal/day = 1650-1800 calories CHO - 55Why should CHO intake be a percentage and not a exact quantity?-%'s need to be balanced against total energy intake
-Athletes who consume large amounts of energy/day may meet their max rate of glycogen resynthesis with CHO respresenting only 40% of total energy - 56How long does it take for replenishment of glycogen stores after exercise?-High carb diet: 24hrs
-Low carb diet: attrition over 3 days - 57What is the purpose of pre-exercise glycogen 'loading'?-To 'super-compensate' or max. muscle glycogen stores
-Delay fatigue & allow maintenance of exercise at mod-high intensity for longer
-We - 58What does effect does pre-event (<4hrs pre-event) intake of CHO have?-Max muscle glycogen stores
-Max liver glycogen stores
-Ensure athlete is adequately hydrated
-Prevent hunger but avoid gastrointestinal discomfort - 59What is Glycaemic Index and what effect does it have on performance?-GI: speed glucose appears in blood
-Low GI meals result in slower rise in blood glucose response
-There is a significant difference in performance between high & low GI meals consumed before exercise - 60What are the priorities during prolonged exercise?-Substrate replacement (prevention of hypoglycaemia and sparing muscle glycogen): will delay fatigue
-Fluid replacement - 61Does CHO intake during exercise have any effect? ('Central' influence)-Can improve mental performance as well as exercise capacity
-Improve performance independent of glycogen depletion - suggesting a central (CNS) effect - 62What role does fat play in the body?-Essential component of cell membranes & nerve fibres
-Primary energy source
-Protects organs
-Stores the fat-soluble vitamins
-Necessary for steroid hormone production
-Provides insulation - 63How is fat used during exercise?-Fat represents the largest fuel reserve for muscles
-Fat transported by blood from adipose cells can be used by muscles, as can fat stored within muscle cells themselves - 64Benefits of High Fat Low CHO diet-Results in adaptations in muscle that favour oxidative phosphorylation
-Improved aerobic capacity in the muscles can reduce the rate at which muscle glycogen is used, delaying athlete hitting the wall - 65Limitations High Fat Low CHO diet-Limitations related to potential to undertake high exercise intensity
-For an endurance athlete in training, exercising for a couple days/wk on low CHO diet may be of value - 66What is the role of protein?-20 AA required, 8 essential must be gained from diet (not created)
-AA & protein contribute to structure, transport, enzyme function, hormone production, immune function, acid-base balance, fluid balance & energy availability - 67Explain the term Biological Value-Measure of proportion of absorbed protein from a food which becomes incorporated in the proteins of body
-How readily the broken down protein can be used in protein synthesis in the cells of the organism
-raw egg = 100 - 68How much protein should athletes consume?-Well trained endurance athletes 1.2-1.6g/kg/d
-Low-mod endurance exercise does not require any more protein than recommendations for sedentary individuals
-Balanced diet will generally reach this - 69Are all high quality proteins the same?-No: full cream milk >influence on muscle protein synthesis than fat-free milk (due to difference in total energy
- 70What is whey protein?-Whey protein elicits greater initial rate of protein synthesis than casein
-Soluble protein quickly absorbed, casein clots in stomach - leading to slower absorption
-Higher leucine content: possibly related to faster protein synthesis - 71What does leucine & other essential AA do?-Stimulates protein synthesis; 6g will initiate synthesis; >20g no increased effect
-Insulin response to EAA intake & insulin = AA's are together important for increasing protein synthesis - 72Is it the amount or timing of protein that has a greater effect?-Timing rather than absolute daily intake for important for athletes seeking hypertrophy
-No adverse health consequences with high protein intake
-Supplementation with specific AA (e.g. glutamine) does not confer any benefit - 73How should fluid be consumed during competition?-Fluid intake in events less than 30min duration will not benefit performance
-For most endurance events (longer than 30 mins) fluid intake, especially when weather causes sweating, is beneficial
-Change in body weight as result of prolonged endurance exercise can be 4kg (6% deficit in body water) - 74How does fluid effect gastric emptying?-Maximising GE is important
-High volumes of fluid can favour high GE
-Keeping the CHO concentration of the sports drink below 6% will reduce the risks of lowering GE - 75What is hyponatremia?-Condition where blood sodium conc/n lower than normal range 135-145mmol/L
-Symptoms: weakness, disorientation, seizures & coma
-Over-consumption of fluid during exercise can lead to hyponatremia & must be resisted - 76Nutrition for recovery after training & competition-6-24hrs separate high intensity training sessions
-Nutritional issues relating to recovery inc. restoration of muscle and liver glycogen, rehydration & repair/growth of tissue - 77How does nutrition effect glycogen resynthesis?-Post-exercise muscle glycogen resynthesis is most rapid within 2-4 hours following exercise
-B/c glucose enters the muscle cell independent of insulin
-So, once exercise has been completed, CHO intake must immediately begin - 78Fluid replacement due to exercise-Athletes only replace 30-60% of fluids lost
-150% of volume lost needs to be consumed
-Na conc/n need to be high to prevent post-exercise excessive urine loss
-Sports drinks contain 10-25mmol/L of Na - not heaps but keeps palatable - 79How is caffeine absorbed?-Absorbed by GI tract within 1hr
-Peak plasma caffeine conc/n reached 15-20min after ingestion
-Exreted in urine w/ half life of 3-5hrs - 80When is caffeine taken by athletes?-Taken off banned list 2004
-Taken 60min prior to exercise in doses equivalent to 6mg/kg - 81How does caffeine affect the athlete's body?-Elicit ergogenic effect independent of glycogen sparing
-Exercise improved in events lasting less than 30min
-Improve Ca homeostasis in muscles & NaK-Pump
-Strength/power & brief sprints
-Increase reaction time but high doses impair fine-motor skills - 82What are the side effects of consuming caffeine?-No adverse effects on sweating or body temp.
-Diuretic effect has little evidence that a burden
-Withdrawal effects of headaches / mood disturbances - 83What is HMB?-Metabolite of leucine, made in body & in citrus & catfish
-Not essential nutrient
-Purported to reduce protein catabolism ->strength training over 3 wks (3d/wk) 3g/d. Suppl. increased muscle mass and strength - 84How does HMB affect well-trained athletes and older people?-Well trained: HMB did not influence strength & LMB over 6wks
-Does not influence reductions in strength associated with DOMS
-HMB may benefit elderly & untrained - 85What is glycerol?-Illegal substance
-In hyperhydration, advantage to improved thermoregulation in heat
-Glycerol suppl. stimulate ADH release, but been disputed in 2 studies - 86How is the glycerol research disputed?-After glycerol ingestion, sweat rate was higher & cre temp. increased were lower
-Equal number of studies showing no effect on HR, OT, sweat rate, RPE
-1 study showed increased time to fatigue @ 60% VO2 Max after glycerol suppl. - 87What are the risks of glycerol consumption?-Large intake could increase risk of cerebral & intraocular dehydration
-Dizziness, nausea, bloating, vomiting & headaches possible - 88What are alkalasing agents: sodium bicarbonate & sodium citrate?-Increase extracellular pH
-Accelerate transfer of H+ from active muscle cells to blood, slowing intramuscular acidosis - 89What is the research behind alkalising agents?-No obvious reason for disparity, may be nausea or training status
-Max exercise causing fatigue around 1-2mins
-300mg/kg bicarbonate, 500mg/kg sodium citrate
-No sig. health problems - 90What is the purpose of B-Alanine supplementation?-Improve muscle carnosine conc/n (which can buffer intramuscular H+)
-8 wks of suppl. improves sprint performance - 91What does research about B-Alanine state?-4 wks suppl. evokes sig. improvements to exercise capacity
- As performance likely limited by accumulation H+ ions in skeletal muscle
-4-6g/d 2+wks increases muscles carnosine content 20-30%, 40-60% wk4, 80% wk10
-Dosage: 4.8g-6.5g/d - 92What are the possible side-effects of B-Alanine supplementation?-Skin irritation
-Flushing
-Tingly sensation (paraesthesia)
-Study showed after 4 wks non-toxicity & blood health markers normal - 93Beetroot Juice as a supplementation-High in nitrate
-Nitrate converted to nitrite then nitric oxide in body
-NO is powerful vasodilator and associated w/ increasing blood flow to tissues such as skeletal muscle - 94What effect does beetroot juice have on performance?-Reduces resting blood pressure & may improve mitochondrial function & muscle efficiency
-Nitrate suppl. reduces O cost to both low-intensiy & high-intensity exercise
-Rapidly absorbed & plasma levels peak 1hr after ingestion
-Effective dose is 500mL - 95What does research around beetroot suppl. say?-Mostly moderately trained subjects
-300-500mL taken before exercise improves exercise capacity in endurance and sprint activities
-No side-effects - 96What is Glutamine?-AA: most abundant in muscle & plasma
-Skeletal muscle is a major producer
-Fuel for lymphocytes (key cells of immune system)
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- Exercise Physiology Exam Preparation
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- Mikaela Sullivan
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