Clickview Link - Chronic Adaptations to training.

Activity:

1. When a person undertakes a thorough and regular training program, what are some of the major changes that occur to the body?

2. Why do these changes occur and what is the benefit of each?

In your own words define the following terms:

• • Resting heart rate

  • Stroke volume

  • Cardiac Output

  • Oxygen uptake

  • Lung capacity

  • Haemoglobin level

  • Muscle hypertrophy

  • Effect on slow-twitch muscle fibre

  • Effect on fast-twticth muscle fibre

Activity:

Clickview - Chronic Cardiovascular Adaptations

Watch the attached clip and complete the interactive Worksheet

Resting heart rate:

• Definition: is the number of times your heart beats per minute at rest.

• PA: Decreased RHR due to more efficient stroke volume.

Stroke Volume

• Definition: is the amount of blood pumped out of the left ventricle of the heart per contraction.

• PA: An increase in stroke volume results from training and allows the same amount of blood to be transported around the body with fewer heart contractions.

Oxygen Output

• Definition: is the amount of blood pumped out of the left ventricle of the heart per minute, and is calculated by multiplying the athlete’s stroke volume by their heart rate.

• PA: Increased cardiac output is a direct result of an increased stroke volume, as an athlete’s maximal heart rate does not increase significantly.

The increase in stroke volume and cardiac output are physiological adaptations that allow for faster and more efficient transportation of blood and the nutrients within it, including oxygen. It means an athlete can remove lactate and carbon dioxide faster and deliver more oxygen and glucose to the muscle as it is needed. This allows the athlete to maintain higher intensities for longer, as lactate removal and oxygen delivery are faster. They can maintain these intensities for longer for the same reasons and because there is a faster delivery of blood glucose and removal of carbon dioxide.

Oxygen Uptake

• Definition: refers to the body’s ability to absorb oxygen through the lungs and into the blood, transport this oxygen sufficiently to the muscle and then transport the oxygen out of the blood and into the muscle cell where it is used for energy production.

• PA: Oxygen uptake increases in response to training and allows for faster and more efficient delivery of oxygen to the muscles.

There are two main reasons for the increase in oxygen uptake: an increase in haemoglobin and myoglobin levels. Myoglobin is responsible for the transportation of oxygen out of the blood and in the muscle cell, taking it to where it is needed for ATP production in the aerobic energy system. Haemoglobin is responsible for absorbing oxygen from the lungs and transporting it through the blood. The more haemoglobin the more oxygen per mL of blood that can be transported.

Lung capacity:

• Definition: refers to the maximum amount of air that your lungs are able to hold

• PA: remains relatively unchanged

Oxygen uptake and lung capacity work together in order to deliver oxygen into the blood so that it can be transferred around the body. Oxygen uptake increases as a result of training causing an increase in the amount of oxygen being transferred in the blood for muscles to use in aerobic activity. However, lung capacity does not seem to change much, if at all, in response to training.

Haemoglobin level:

• Definition: Haemoglobin is a protein in your red blood cells that carries oxygen to your body's organs and tissues and transports carbon dioxide from your organs and tissues back to your lungs.

• PA: Haemoglobin levels increase in response to training and improve the body’s ability to transport oxygen to the muscles where it is needed for energy production.

This increased usage of the aerobic energy system delays the need to rely on the anaerobic energy systems and therefore helps avoid fatigue caused by the build up of acid in the muscle. Therefore, an increased haemoglobin level increases the workload at which the athlete reaches their anaerobic threshold. This allows the athlete to have a maintain higher intensities for longer periods of time, because they remain within their aerobic training zone.

This also improves performance by allowing faster recovery from acid build up, which then allows higher anaerobic intensities to be used with shorter rest periods between each anaerobic workload.

Muscle Hypertrophy:

• Definition: Muscular hypertrophy is an increase in the size of the muscle

• PA: Muscular hypertrophy results in an increase in muscular strength and muscular endurance. This helps improve performance by allowing the athlete to exert a greater force and to repeat movements more often. Often hypertrophy will also increase muscular contraction speed allowing greater power to be produced during contraction.

This is very beneficial in sports that require, strength, power, or muscular endurance. Such sports include: shot put, sprinting, rugby, NFL, AFL, Ice-hockey, and martial arts.

Effects on slow-twitch and fast-twitch muscle fibres Fast vs Slow (Youtube clip 3mins)

• Slow twitch - Slow twitch muscle fibres are used for movements that have a long duration. They are red in colour because of the extra blood supply they have in order to assist the aerobic energy system. The adaptations within these muscles assist in the use of the aerobic energy system and include increased: mitochondria, capillary density, aerobic enzymes needed for ATP production in the aerobic energy system, glycogen and fat stores, and myoglobin. All of these adaptations help in the delivery of ATP through the aerobic energy system.

• Fast twitch - Fast twitch muscle fibres are the fibres used for strength, power, and movements of high intensity and short duration. They can be linked with the two anaerobic energy systems, which means the adaptations in these fibres help in the use of these systems. Adaptations include increased anaerobic enzymes for glycolysis, increased PC stores, hypertrophy and increased removal of lactate, which helps reduce the acidic levels in the muscle.

• PA: Training has an array of effects on fast and slow twitch muscle fibres which are specific to the type of training. Some of these adaptations are similar, such as: increased capillary density, which increases the delivery of blood to the muscle cells. An increase in mitochondria in the muscle cell, which increases ATP production from eh aerobic energy system. As well as increased myoglobin, which transports oxygen from the blood through the muscle to the mitochondria. However, other adaptations are specific to the muscle type.

Extension Activity:

• For this activity you will need to record and compare resting heart rates (HR) and stroke volumes (SV) for a group of people – this could be as few as three or four, or your entire class.

• Resting heart rate will be directly measured, and using a typical average figure for cardiac output (Q), stroke volume will be calculated. Once the data is collected, you are required to analyse and discuss.

1. Measure and record the resting heart rates of each person in your group.

2. Assuming a typical cardiac output figure of 5 l/min, use the formula: SV = Q/HR to calculate each person’s stroke volume. Express answers in both ml and l.

3. Have everyone in the group or class provide a point-form description of their own exercise/training regime.

4. Present the group’s data for HR and SV both in a table and on a graph.

5. In addition, include data about each person’s exercise/training regime. This could appear as part of the graph (depending on the number of people in the group), or could be written up in a separate document.

6. Analyse the results for your group. Write a report of up to 200 words commenting on the following:

 HR and SV figures and whether there is a clear relationship among the different individuals between their HR and SV.

 The amount and type of regular exercise they do.

 Does it generally follow that those who do a lot of regular moderate to high intensity exercise show lower resting HR levels and therefore a higher SV?

 Are there any anomalies in the group’s results?