Exercise Physiology

Question 1

What are the 3 metabolic pathways?

Answer 1

phosphocreatine, glycogen, glucose fatty acids and amino acids

Question 2

What is the phosphocreatine pathway?

Answer 2

ATP breakdown
- ATP <–> ADP + Pi + Energy + H+
- occurs rapidly at exercise onset

ATP resynthesis
- PCr + ADP + H+ <–> ATP + Cr
- Enzyme - Creatine kinase

Short-term, intense exercise
Anaerobic – no oxygen

Question 3

What is glycolysis?

Answer 3

• provides 90s of muscle energy
• breakdown of glucose/glycogen into pyruvate (with O2) or lactate (without O2)
• 2 phases, energy investment and generation
• net gain of 2ATP from glucose
• net gain of 3ATP from glycogen

Question 4

What is the aerobic system?

Answer 4

• Oxidation of foodstuffs in the mitochondria to provide energy
• Citric acid cycle (Krebs cycle)
• Electron transport chain
• Aerobic metabolism can last indefinitely

Question 5

Compare usage of the different systems

Answer 5

~100% ATP-CP
- 100m sprint, weight lifting

ATP-CP/anaerobic glycolysis
- 200-400m sprint, basketball

Anaerobic glycolysis/aerobic
- Middle distance running

Aerobic
- Marathon, road cycling

Question 6

Explain pulmonary ventilation and oxygen consumption

Answer 6

Oxygen consumption for a young male is ~ 0.25 L/min
- Can increase ~ 20 fold between resting and maximal intensity

Pulmonary ventilation at maximal exercise = 100-110 L/min
- Maximal capacity = 150-170 L/min

Provides extra ventilation during
- High altitudes
- Exercise in hot/humid environments
- Abnormalities in the respiratory system

Question 7

What is VO2 max

Answer 7

• VO2 max is the rate of oxygen usage under maximal aerobic metabolism
• Oxygen uptake increases linearly until maximal oxygen uptake (VO2 max) is reached
• VO2 max occurs when pulmonary ventilation at 60-70%
• VO2 max is the ‘Physiological ceiling’ for delivery of oxygen to muscle
• Affected by genetics and training
• Physiological factors influencing VO2 max
• Maximum ability of cardiorespiratory system to deliver oxygen to the muscle
• Ability of muscles to use oxygen and produce ATP aerobically

Question 8

What is oxygen diffusing capacity?

Answer 8

• rate at which oxygen can diffuse from pulmonary alveoli into the blood
• measured in mL of oxygen that diffuses each min for each mL of mercury difference between partial pressure of oxygen in alveoli and pulmonary capillaries

Question 9

What is the relationship between muscle blood flow and exercise?

Answer 9

• blood flow inc is as important as dec
• contractile process temporarily dec muscle blood flow due to compression of intramuscular blood vessels
• blood flow to muscles inc markedly during exercise

Question 10

What is the relationship between work, cardiac output and oxygen consumption

Answer 10

cardiac output = heart rate x stroke volume
- stroke vol is amount of blood pumped per heartbeat
- during exercise CO is increased by both HR and Sv

Question 11

What is heart hypertrophy?

Answer 11

• Marathoners and endurance athletes can achieve maximal cardiac outputs that are ~40% greater than untrained persons.
• Heart mass and heart chambers enlarge by ~40%.
• Increase in heart-pumping effectiveness is the key.

Question 12

Explain the cardiac system as a limiting factor

Answer 12

• cardiac output is 90% the max a person can achieve during exercise
• pulmonary system 65%
• oxygen utilisation by body can never be more than the rate at which cardiovascular system can transport oxygen to tissues

Question 13

What causes excess O2 consumption?

Answer 13

• resynthesis of PC in muscle
• lactate conversion to glucose
• restoration of muscle and blood oxygen stores
• elevated body temperature
• post-exercise elevation of HR and breathing
• elevated hormones

Question 14

How is lactate removed after exercise?

Answer 14

classical theory
- majority converted to glucose in lever

recent evidence
- 70% lactate oxidised (substrate by heart and skeletal muscle)
- 20% converted to glucose
- 10% converted to amino acids

lactate removed more rapidly with light exercise in recovery
- optimal intensity is ~30-40% VO2 max

Question 15

What factors are dependent of diet?

Answer 15

restoration of glycogen and exercise capacity

Question 16

What are the contractile forces of muscle?

Answer 16

maximal contractile force between 3 and 4kg/cm2 of muscle cross-sectional area

holding strength of a muscle is 40% greater than contractile strength

Question 17

What is the relationship between muscle work and power?

Answer 17

when muscles contract they produce tractive forces (tension) that act on muscles’ insertions
- isometric, concentric, eccentric

work = f (applied by muscle) x d (over which force is applied)

power = work/time

Question 18

Describe fast and slow twitch muscle fibres

Answer 18

different categories based on biomechanical and contractile properties

slow twitch = type 1
fast twitch = type 2x and 2a

Question 19

How do muscles adapt to resistance training?

Answer 19

• muscles that function under no load increase little in strength
• resistance training is conducted to induce changes in muscle size
• hyperplasia (inc in number) or hypertrophy

Question 20

Explain muscle hypertrophy

Answer 20

• englargement of both type 1 and 2 fibres
• greater hypertrophy in type 2
• inc in myofibrillar proteins
• increases number of cross-bridges
• inc ability to generate force
• resistance training activates satellite cells to divide and fuse with adjacent muscle fibre to inc number of nuclei in fibre

Question 21

Explain sex differences in body composition

Answer 21

• men have more lean mass, woman have more fat
• testosterone leads men to have larger muscle mass and lwoer body fat %
• normalised to muscle vol, bodyweight or fat free mass, strength difference between male and female athletes are minimal
• women possible ‘less fatiguable’ than men in isometric/concentric muscle actions

Question 22

What are the unique challenges of para-sport?

Answer 22

• inc value of practitioner input
• limited published data
• heterogeneity
• many sports are unique
• most situations demand interdisciplinary input

Question 23

What are impairment specific conditions?

Answer 23

amputees
- less surface area for dissipating heat

spinal cord injuries
- limited sweating and blood flow redistribution below lesion

cerebral palsy
- movement inefficiency leading to inc metabolic heat production

multiple sclerosis
- often experience a worsening of symptoms when exposed to heat

other neurological impairments

Question 24

Why is heat preperation imporatant?

Answer 24

heat stress can come from prolonged passive or active exposure.

without prep, heat can compromise physical and cognitive performance
- reduction in physical capacity
- thermal discomfort
- impaired decision making and skill execution

Question 25

Explain heat acclimation

Answer 25

repeated exposure to hot conditions to maximise physiological adaptions
- reduces risk of heat illness
- training stimulus
- improves performance and thermal comfort in the heat]
- 75-80% of adaptions occur within 4-7 days, more complete adaptions require 14 days of exposure

Question 26

How can heat acclimation be completed?

Answer 26

passive or active methods
- training outdoors or in a heat chamber
- resting in a sauna or spa (post exercise)

tailor environmental conditions and sessions to suit adaption objectives

heat stress is an additional load
- maintenance of training intensity can be impacted
- fatigue levels will likely be greater
- adequate rest/recovery is necessary to maximise adaptions
- prioritise sleep

Question 27

What are impairment-specific considerations?

Answer 27

inability to thermoregulate effectively
- impaired/absent sweat response
- impaired blood flow control

increased concern of overheating and decrements during exercise in the heat

Question 28

Give an example of gastrointestinal temperature with spinal cord injuries

Answer 28

athletes with TP had a greater change in gastrointestinal temp than AB

athletes with HP had a greater change in gastrointestinal temp than LP and AB

Question 29

What is performance recovery?

Answer 29

• process of restoring body to pre-exercise state
• recovery from training and competition, not from injury
• physical and psychological recovery

Question 30

what are some recovery strategies?

Answer 30

stetching
hydrotherapy
massage/relaxation
compression garments
active recovery/warm down
sleep and nutrition and hydration

Question 31

What are recovery considerations?

Answer 31

• type of exercise session
• are the athletes prone to injury
• are the athletes in a training camp/intensive training/ competition phase

Question 32

What are impairment specific recovery considerations?

Answer 32

• increased incidence of injury and illness among para-athletes
• incidental load for para-athletes who use a wheelchair during sport and everyday activities, or those with movement inefficiencies
• additional fatigue from impaired thermoregulation

strategies should target the specific risk factors or challenges arising from the impairment

Question 33

Case study - sleep

Answer 33

• averages between 9-9.5hr in bed
• needs 7.5 to feel rested
• bedtime: 10pm
• waketime: varies according to # of wake bouts
• awake 2hr per night from 2am
• improved sleep environment (bigger bed, no dog, motionles mattress)
• mindfullness and trigger ball therapy prior to bed

solution
- seek light 7-11
- avoid light 2:30-4
- bed time 22
- wake time 7

Question 34

case study - wheelchair basketball
para-athlete condiserations in hot and humid conditions

Answer 34

impairment considerations
- mens: T4-T12 SCI, spinda bifida, amputee
- womens: T4, T10 and 11 SCI, CP, spina bifida, amputee. ta;o[es eqionoveras

physiological considerations
- thermoregulatory capacity
- sweat capacity
- perceptual responses (thermal comfort)

strategies
- pre-, during, and post-cooling
- normalising heat

Question 35

case study - para athletics
recovery programming example

Answer 35

• reporting constant fatigue
• coach: inability to back up, concern with training consistency
• sleep hygiene = excellent

plan
- assess weekly training schedule and extra activities with athlete and coach
- discuss potential strategies
- develop a structured intervention, built into training plan

implement
- intermittent pneumatic compression (legs) post-training 3/week plus 1 on weekend
- increase ice bath immersion duration
- add floatation

review
- fortnightly review with athlete to evaluate plan
- ensure coach is updated and involved in review process as required
- make adjustments as required