ACUTE AND CHRONIC RESPONSES TO EXERCISE

Acute circulatory & respiratory response to exercise

Short-term or immediate responses to exercise on the cardio-respiratory system.

• Increased heart rate (HR: of beats per minute) – increases to meet the increased demand for oxygen during exercise. Heart will beat faster to increase the volume of blood being pumped around the body

• Increased stroke volume (SV: the volume of blood pumped from the left ventricle of the heart per beat) – increases to meet the blood and oxygen demand of increased exercise.

Acute circulatory & respiratory response to exercise cont.• Increased cardiac output (Q: the volume of blood pumped

around the body in a minute) – increased to meet the increased oxygen demands during exercise.

• Increased Arterio-venous oxygen difference (a-v O2 diff.: The difference between the oxygen concentration in the artery compared to the veins) – reflects the amount of oxygen taken from the blood capillaries by the muscles.

Acute circulatory & respiratory response to exercise cont. • Increased blood flow – To meet the oxygen demands of

increased exercise.• Changes in blood lactic acid levels – lactic acid levels

increase from rest.• Decreased blood volume – Decreased blood plasma

volume as if is forced out of the capillaries due to increased blood pressure.

Acute circulatory & respiratory response to exercise cont.• Increased ventilation (VE: the process where air is moved

in and out of the lungs per minute) – to meet the oxygen demands of increased exercise.

• Tidal Volume – the volume of air moved in and out of the lung per breath.

• Breathing frequency – the number of breathers per minute• Increase lung diffusion – increase of oxygen diffused into

the blood stream

Acute circulatory & respiratory response to exercise cont.Blood Pressure increases to meet the demands of oxygen during exercise.

• Systolic blood pressure – the pressure exerted on the blood vessels when the left ventricle contracts.

• Diastolic blood pressure – the pressure exerted on the blood vessels when the left ventricle relaxs.

Acute muscular response to exerciseThe short term or immediate response to exercise on the muscular system.

• Increased motor unit activation – the muscle neuron is stimulated to contract , all the muscle fibres in that unit will simultaneously contract 100% on each effort.

• Selective recruitment – the use of slow twitch or fast twitch fibres in the muscles contractions.

• Increased muscular temperature – heat in generated by blood flow and ATP resynthesis

• Decrease in fuel stores – decrease of CP, Glycogen and Triglycerides. All three stores suffer depletion during exercise to a certain degree.

• Increased enzyme activity – enzymes are responsible for speeding up the rate of reaction within the skeletal muscles increase their activity level.

Chronic responses to anaerobic trainingChronic responses are the result of repeated training over a period

of time.

• Increased muscular strength – as a result of muscular hypertrophy and the ability to recruit a greater number of motor units during exercise.

• Increased fuel stores – ATP and CP stores in the skeletal muscle. • Increased glycogen stores – within the skeletal muscle.• Increased lactic acid tolerance – can exercise for with higher

levels of muscle and blood lactic acid.• Increased lactic acid utilisation – muscles improved capacity to

metabolise lactic acid and convert it back to pyruvic acid and glycogen.

• Increased flexibility – increased range of motion, increased resting length of muscles and decreased resistance to joint movement.

Chronic responses to aerobic training• Cardiac hypertrophy – increase in the size and volume of

the left ventricle of the heart.• Increased blood volume – results in increased red blood

cell count, therefore increased haemoglobin. • Increased number and size of mitochondria – increased

within the muscle cells which results in a greater capacity for aerobic respiration.

Chronic responses to aerobic training cont.Increased oxygen delivery

• Increased capillarisation – the density of capillaries surrounding the trained muscle tissue increases significantly with endurance training.

• Increased red blood cells – results in more oxygen being ‘picked up’ and transported around the body.

• Increased myoglobin – greater oxygen being transported around the body.

• Increased pulmonary diffusion – greater ability for oxygen to be diffused from the alveoli in the lungs across the pulmonary capillaries into the blood for transport to the active muscles.

• Residual volume – the volume of air remaining in the lungs after maximal expiration.

Chronic responses to aerobic training cont.

• Increased fuel stores – muscle and liver stores increased through endurance training.

• Increased respiratory function – with repeated exposure to endurance training the strength of the respiratory muscles increase.

• Decrease in total body fat and increase in lean body weight.

• Lowering of cholesterol balance.

Chronic responses to sub-maximal exercise

• Heart rate/stroke volume/cardiac output – the enlarging of the left ventricle chamber.

• Blood pressure – decrease of blood pressure.• Increased blood volume and haemoglobin.• Increased blood flow to the working muscles.• Increased minute ventilation – increased amount of air

inspired and expired within a minute. • Increased Arterio-venous oxygen difference – due to the

body being able to extract oxygen from the blood easier.• VO2 – increased oxygen consumption.

Chronic responses to sub-maximal exercise cont.

• Muscle glycogen depletion – decrease in the amount of muscle glycogen used as the body gets better at utilizing fatty acids as an energy source.

• Decreased lactic acid production/accumulation – increased mitochondria for greater aerobic respiration, smaller oxygen deficit, greater use of lactic acid as a fuel source & increased reliance on fatty acids as fuel sources.

• Anaerobic threshold – increased ability for the body to supply ATP during exercise.

Chronic responses to maximal exercise cont.

• Unchanged Heart rate• Increased stroke volume/cardiac output• Increased muscle blood flow• Increased VO2 max• Increased Ventilation minute – tidal volume x breather

frequency• Increased in lactic acid production and utilization

How to analyse a specific sport• What are the dominant energy systems?

• What is the intensity? o Maximal – anaerobico sub-maximal - aerobic

• What is the time frame?o 0-10 seconds of maximal intensity - ATP-CPo 0-90seconds of high intensity – lactic acido 2-3minutes+ of low intensity – aerobic

• What is the work-rest ratio?o Total work time : total rest timeo Average work and rest time

Volleyball

Energy system Game Play Example

ATP-CP System

Lactic Acid System

Oxygen System

Consider a few game play example specific to volleyball that would be dominated by the three different energy systems.

Fitness components/factorsHealth related factors Description

Cardio-respiratory endurance

Capacity of your heart, blood vessels and lungs to function efficiently during vigorous sustained activity.

Flexibility The ROM possible at a particular joint or series of joints.

Muscular endurance The capacity of a muscle to repeatedly exert a force or to hold a fixed or static contraction over a period of time.

Muscular strength The maximum force that can be generated by a muscle or group of muscles in a single maximal contraction.

Body Composition The make up of the body, taking into consideration the relative proportions of fat mass and fat free mass, which includes components like bone and muscle – often expressed as a % body fat.

Skill related factorsSkill related factors

Description

Agility The ability to change direction quickly and accurately while maintaining balance.

Balance Maintaining body equilibrium while static or dynamic.

Coordination Accurate movement of body parts, to produce smooth, controlled actions.

Muscle power The maximum force that can be exerted in the shortest possible time. A combination of speed and strength.

Speed How quickly a body part can be put into motion – speed of muscle contraction

Reaction time Time it takes to respond to a stimuli.

What fitness component and skill related factors are relevant to volleyball?