pe - unit 4 aos 3

chronic adaptations to exercise

• chronic adaptations are the physiological changes that occur in response to the increased demands placed on the body during training. chronic adaptations lead to improved performance.

• types of chronic training adaptations

  • aerobic adaptations

  • anaerobic adaptations

  • resistance adaptatioms

• adaptations can also be classified as structural (physical change, ex, heart size, muscular hypertrophy) or functional (ex, tidal volume). it is easier for for a functional adaptation to occur. some structural adaptations take 6 months - a year to occur

• these chronic adaptations ultimately produce improvements in one of: (link everything back to one of four areas)

  • VO2 max

  • lactate inflection point

  • increased speed + force of muscular contraction

  • lactate tolerance

aerobic training - cardiovascular adaptations

• increased heart size

• increased stroke volume

• increased cardiac output

• decreased heart rate

• increases heart capillarization

• decreased blood pressure

• increased blood volume

aerobic training - cardiovascular adaptations - heart size, stroke volume, cardiac output

• with aerobic training, the size of the heart increases (left ventricle)

• → increase in heart size increases stroke volume

• during exercise, the increased SV results in an increased cardiac output → greater volume of blood ejected from the heart per beat results in more oxygen for the athlete to use

• at rest + submaximal exercise, even though SV is increased, there is also a lower HR, so cardiac output doesn’t change

aerobic training - cardiovascular adaptations - heart rate

• aerobically trained athletes have very low resting heart rates

• bradycardia

aerobic training - cardiovascular adaptations - heart capillarisatrion

aerobic training - cardiovascular adaptations - blood pressure

• systolic bp decrease at rest

• no decrease in systolic bp during exercise

• no change in diastolic bp

• haemoglobin - the part of red blood cells that attracts oxygen to bind to the RBC

• increase in haemoglobin

• increase in plasma → more opportunity to sweat before get dehydrated + also more nutrients transported around body

• =

aerobic training - cardiovascular adaptations - blood volume

aerobic training - cardiovascular adaptations - capillarisation

• under aerobic training, blood vessels will:

  • increase in cross-sectional area

  • show increased capillarisation to heart and skeletal muscles

• → increased capillarisatio increase oxygen supply to muscles and enhances waste removal

aerobic training - respiratory adaptations

• increased tidal volume* (max capacity)

• decreased respiratory rate

• increased pulmonary diffusion

• increased pulmonary ventilation

aerobic training - respiratory adaptations - tidal volume + respiratory rate

• structural change of lung volume → functional change of increased tidal volume (amount of oxygen breathed in or out in one breath). → ventilation more efficient (more oxygen per breath)

• an aerobically trained athlete does not need to breathe as frequency (respiratory rate decreases), → ventilation more efficient

aerobic training - respiratory adaptations - pulmonary diffusion

• aerobic training results in an increase in the surface area of the alveoli, which in turn increases pulmonary diffusion

aerobic training - respiratory adaptations - pulmonary ventilation

• oxygen consumption when working maximally increases as a result of all adaptations

lactate tolerance, vo2 max in transport of oxygen

aerobic training - muscular adaptations

• (all basically oxygen utilisation)

• increased oxygen utilisation

• increased oxidative enzymes

• fibre type adaptation

• fuel stores

• mitochondria

• myoglobin a-VO2 difference

aerobic training - muscular adaptations - oxygen utilisation

• aerobic training enhances the body’s ability to attract oxygen into the muscle cells and then use it tp resynthesise ATP to then be used for muscular contractions

aerobic training - muscular adaptations - oxidative enzymes

• oxidative enzymes oxidate H+ ions

• an increase in oxidative enzymes allow athletes to work for longer without accumulating blood lactate

aerobic training - muscular adaptations - fibre types

• slow twitch fibres … fast twitch fibres…

• slow twitch naturally have a higher density of mitochondria.

• aerobic training will increase the size/number of slow twitch fibres and therefore increase mitochondria in the body → increase aerobic power

aerobic training - muscular adaptations - fuel stores

• increased fuel stores

• aerobic training increases the muscular storage of glycogen and triglycerides in the slow twitch muscle fibres. this is because there is more/bigger slow twitch fibres.

aerobic training - muscular adaptations - oxidation of fats

• the oxidation of free fatty acids allow for glycogen conservation

• prolong the switch of fats to glycogen as an energy source during exercise

• this process is referred to as glycogen sparing. this allows the athlete to sustain a higher level of intensity, maintaining a faster pace + for a longer time.

aerobic training - muscular adaptations - mitochondria

• mitochondria is the site of aerobic ATP production.

• aerobic training increases the size, number and surface area of mitochondria in muscle cells, enhancing ATP production/resynthesis.

aerobic training - muscular adaptations - myoglobin

• in a cell, myoglobin attatches to haemoglobin, and brings it (+ therefore oxygen) to the mitochondria through the cytoplasm

• aerobic training increases myoglobin → increases oxygen delivery from blood to mitochondria in working muscle cell

aerobic training - muscular adaptations - a-vo2 diff

• A-VO2 difference is the difference in oxygen concentration in the arteries compared to the veins

• aerobic training increases the A-VO2 diff, meaning muscles will extract more oxygen from the blood

anaerobic training - cardiovascular adaptations

• only one

• increased thickness of the left ventricle wall

anaerobic training - muscular adaptations

• increased muscle hypertrophy

• increased fuel stores (PC + glycogen in muscle)

• increased motor unit recruitment

• increased lactate tolerance

• increased enzymes

anaerobic training - muscular adaptations - hypertrophy

• anaerobic training can lead to significant enlargement of muscle fibres (mainly fast-twitch), muscular hypertrophy, increased cross-sectional size of muscle fibres. →greater speed + force of contraction → greater strength

anaerobic training - muscular adaptations - fuel stores

• more room in fast twitch fibres allows for increased ATP and PC stores → increases capacity of ATP-PC system

• increased glycogen stores which allows for an increase of glycogen utilisation

anaerobic training - muscular adaptations - motor unit recreuitment

• the greater number of motor units that can be recruited, the greater the strength and power that can be produced by a muscle

anaerobic training - muscular adaptations - lactate tolerance

• muscles with good lactate tolerance can contract maximally even when theres lots of lactate taking up space

• an increase tolerance to lactate results in an increased ability to continue working at high intensities

anaerobic training - muscular adaptations - enzymes

• increased glycolytic enzymes results in an increased rate of ATP release from glycogen

ATPase - enzyme that speeds up the process of ATP resynthesis

resistance training - muscular adaptations - myosin + actin filamnets

• increased number of myosin + actin filaments results in increased speed + force of contractions

• → more myofibrils

resistance training - neuromuscular adaptations

• increased muscle size

• muscle fibre type adaptation

• neural control

• motor unit synchronisation

• increased firing rate of motor units

• inhibitory signals

inhibitory mechanisms stop body from contracting when the body thinks it could hurt itself