PE Unit 4 AOS 2 (Chronic adaptations)

Chronic adaptations

the body's long-term responses of the cardiovascular, respiratory and muscular systems that develop over a period of time when training is repeated regularly. allow the body to better cope with the demands placed upon it

Chronic adaptation to aerobic training: respiratory

-increased pulmonary ventilation during maximal exercise

-increased tidal volume

-decreased resting and submaximal respiratory rate

-increased pulmonary diffusion

Increased pulmonary ventilation during maximal exercise

the movement of air into and out of the lungs.

ventilation is increased because of increased TV and RR

Result: better respiratory efficiency and increased oxygen uptake.

Increased tidal volume

increased amount of air inspired and expired by the lungs per breath, attributed to increased strength and endurance of the respiratory muscles allowing exhale and inhale of more air.

Result: greater amount of oxygen diffused into the alveoli capillaries and delivered to working muscles.

Decreased resting and submaximal respiratory frequency

The number of times an athlete breathes in and out /min is reduced. This is due to improved pulmonary function and capacity. Training improves the efficiency of the diaphragm and intercostal muscles.

Result: function more effectively with each breath.

Increased pulmonary diffusion

results in an increase in the surface area of the alveoli. this increases the amount of O2 and CO2 that can be extracted/exchanged between alveoli and surrounding capillaries.

Chronic adaptations to aerobic training: cardiovascular

-increased left ventricle size and volume

-increased capillarisation of the heart muscle

-increased stroke volume

-decreased resting HR

-decreased HR during submaximal workloads

-faster HR recovery rates

-increased cardiac output during maximal exercises

-decreased BP

-increased capillarisation of skeletal muscle

-increased blood volume

Increased left ventricle size and volume

-cardiac hypertrophy.

-increase in the size, and therefore volume, of the ventricular chambers, particularly the left ventricle

Result: significantly increases SV and Q at maximal intensities, allowing a greater volume of blood to be ejected from the heart and providing more O2.

cardiac hypertrophy

an enlargement of the heart muscle as a result of training

increased capillarisation of the heart muscle

Cardiac hypertrophy -> increase in the capillarisation of the heart muscle (angiogenesis).

Allows the heart to beat more strongly and efficiently during both exercise and rest.

Result: provides a greater surface area for the exchange of gases and nutrients, enhances oxygen supply, removal of CO2 and also the delivery of nutrients to the heart.

capillarisation

an increase in the capillary density and blood flow to skeletal or cardiac muscle as a result of aerobic training

Increased stroke volume of the heart

increased stroke volume allows more oxygen to be delivered to the working muscles, allowing the athlete to use more oxygen and thus improves their ability to resynthesise ATP aerobically.

Decreased resting heart rate

if an individual has developed a greater stroke volume, the heart does not have to beat as frequently to supply the required blood flow (and oxygen) - the heart is more efficient.

Decreased heart rate during submaximal workloads

regular aerobic training results in a slower increase in HR during exercise and a faster attainment of steady state during (less oxygen deficit)

Faster heart rate recovery rates

the heart rate will return to resting levels in a much shorter time. This is due to the greater efficiency of the cardiovascular system to produce energy aerobically.

Increased cardiac output during maximal exercises

only during max exercises and is due to the increase in SV as max HR changes due to training are usually minimal.

Decreased blood pressure

improved blood vessel elasticity and function and reduced peripheral resistance contribute to a more efficient blood flow.

Increased capillarisation of skeletal muscle

greater capillary supply means increased blood flow, allowing greater supply of oxygen and nutrients to the muscles and increased removal of by-products

Increased blood volume

allows for greater amount of oxygen to be transported and delivered to working muscles (due to increased red blood cell amount and blood plasma)

Chronic adaptations to aerobic training: muscular

-increased myoglobin stores

-increased mitochondria size and number

-increased a-vo2 diff

-increased muscular fuel stores and oxidative enzymes

-increased oxidation of glucose and triglycerides

-adaptation of muscle fibre type

Increased size and number of mitochondria

sites of aerobic ATP resynthesis where glycogen and triglyceride stores are oxidised. Greater ability to resynthesise ATP aerobically.

Increased myoglobin stores

Myoglobin is responsible for extracting oxygen from the red blood cells and delivering it to mitochondria in muscle cells.

Result: Increases amount of oxygen delivered to the mitochondria for energy production.

Increased a-vo2 diff

able to extract more O2 from bloodstream into muscles, indicating a greater uptake of O2 and greater capacity to produce energy aerobically

Increased muscular fuel stores and oxidative enzymes

-increases storage of glycogen and triglycerides in slow twitch muscle fibres

-increases metabolism of fuel stores aerobically

Increased oxidation of glucose and triglycerides

increased oxidation of fats means the athlete can rely less on glycogen (glycogen sparing), allowing them to sustain higher levels of intensity

glycogen sparing

the process whereby glycogen stores are not used as early in an exercise bout due to the increased ability to use triglycerides to produce energy. This delays depletion of glycogen stores, and thereby delays the time to exhaustion.

Adaptation of muscle fibre type

-fast twitch type A (oxidative) can take on characteristics of slow twitch

-fast twitch type B (glycolytic) are recruited in a manner that is more like 2A fibres

Types of muscle fibres

type 1 slow twitch oxidative (aerobic)

type 2A fast twitch oxidative (anaerobic long term)

type 2B fast twitch glycolytic (anaerobic short term)

General aerobic chronic adaptations

-increased maximum oxygen uptake (VO2 max)

-increased lactate inflection point (LIP)

Increased maximum oxygen uptake (VO2 max)

comes because of adaptations such as increases in cardiac output, red blood cell numbers, a-vo2 diff, muscle capillarisation, increased myoglobin

VO2 max

the maximum amount of oxygen per minute that can be taken in, transported and utilised by the body for energy production

Absolute VO2 max

a measurement of the total amount of oxygen consumed in L/min

DOES NOT ALLOW FOR COMPARISON BETWEEN ATHLETES

Relative VO2 max

a measurement that takes into account body weight and is given in mL/kg/min

ALLOWS FOR COMPARISON BETWEEN ATHLETES (determines how much oxygen is used per kilogram of body weight.)

Lactate inflection point (LIP)

the highest intensity point at which there is a balance between lactate production and removal from the blood. It represents a person's highest steady state intensity.

Increased LIP

-means that the aerobic system can produce energy at a faster rate, so there is less reliance on the anaerobic glycolysis system until higher exercise intensities are reached.

-lactate and H+ accumulation is delayed

-LIP is more likely to distinguish between middle and long distance athletes (as opposed to VO2 max comparison)

Muscular adaptations that lead to increased LIP

-increased mitochondria size and number (increased pace of ATP resynthesise aerobically)

-increased oxidative enzymes (increased capability to oxidise fats and carbs)

Chronic adaptations to anaerobic training: muscular

-muscular hypertrophy

-Increased fuel stores and enzymes

-Increased glycolytic capacity

-Increase in the ability to recruit more motor units

-Increase in lactate tolerance

-Cardiac hypertrophy

Muscular hypertrophy

Enlargement of skeletal muscle fibres (mainly 2A and 2B) in response to overcoming force.

This occurs due to an increased size and number of myofibrils per muscle fibre and increased amounts of myosin and actin myofilaments

Fuel stores and enzymes

-increased muscular stores of ATP and CP, increasing capacity of ATP-CP system and faster ATP resynthesis

-increase in enzymes required to breakdown and resynthesise ATP (ATPase and creatine kinase)

Increased glycolytic capacity

enhanced muscular storage of glycogen and increase in the levels of glycolytic enzymes (glycogen synthase) which can facilitate storage of glycogen in the muscles

Increase in the ability to recruit more motor units

increased ability of nerve axons to stimulate their corresponding fibres (increased motor units=increased strength and power)

Cardiac hypertrophy

increase in thickness of the ventricular walls, meaning a more forceful contraction takes place to eject blood

Increased lactate tolerance

delays the onset of fatigue and allows an athlete to continue to generate ATP anaerobically, which occurs at a faster rate and allows them to work at a higher intensity.

(increased the ability of the muscles to neutralise acid that accumulates)

buffering capacity

the ability of the muscle cell buffers to resist changes in pH (acidity)

Chronic adaptations to resistance training: neuromuscular

-increase in muscle size and change in muscle structure

-muscle fibre type adaptations

-increased synchronisation of motor units

-increase in the firing rate (rate coding) of motor units

-reduction in inhibitory signals

Increase in muscle size and change in muscle structure

increased strength, size and cross sectional area due to an increase in cross sectional area of each individual fibre

Muscle fibre type adaptations

type 2 fast twitch fibres show greater increases in size, particularly with higher loads, compared to type 1 slow twitch fibres.

Neural control

in absence of hypertrophy, neural adaptations play a critical role in increased force production of a muscle from resistance training (particularly strength gains in the early stages of a program)

Increased synchronisation of motor units

to recruit more motor units at the same time and stimulate larger motor units earlier creates a more powerful muscular contraction with greater force application

Increase in the firing rate (rate coding) of motor units

increases the rate of force development (how quickly a muscle can contract maximally), which is beneficial for ballistic movements.

Rate coding

refers to the frequency of impulses sent to a muscle

Reduction in inhibitory signals

resistance training can gradually override or reduce the inhibitory mechanisms and allow for a greater force production within a muscle group.

Role of the inhibitory system

to provide an important protective reflex that limits an excessive generation of force within a muscle, preventing muscles from exerting force that is greater than they can tolerate.

Chronic aerobic adaptations (time, general focus and training methods)

-6weeks, more noticeable at 12 weeks

-designed to bring about more efficient delivery of larger quantities of oxygen to working muscles

-continuous, fartlek, long interval, HIIT, aerobic circuit training and high-rep low-weight resistance training

Chronic anaerobic adaptations (time, general focus and training methods)

-6weeks

-greatest adaptations to muscular system, improves capacity to generate ATP anaerobically and force production

-short and intermediate interval, plyometrics, circuit and resistance (strength and power) training.

Chronic resistance training adaptations (time, general focus and training methods)

-8-10 weeks (mainly neuromuscular)

-increases in strength

-power and strength=anaerobic, LME=aerobic, mainly neuromuscular