Physiological adaptions to training
- Resting Heart Rate- The heart consists of cardiac muscle and like any muscle that undergoes training it will undergo hypertrophy and become more efficient. A consequence of training is a lower resting heart rate than pre training. This is due to a more efficient cardiovascular system as well as stroke volume.
- Stroke Volume and Cardiac Output- The stroke volume is the amount of blood pumped out of the heart per beat. As the heart becomes more efficient, the left ventricle actually becomes bigger and as a result will pump more blood out per beat than pre training. Cardiac output is the amount of blood pumped out of the heart per minute by the heart. To calculate this, multiply the stroke volume by the heart rate. As the stroke volume is bigger, the cardiac output will rise accordingly due to training. This then increases the amount of blood being sent around the body.
Cardiac output (CO) = Stroke volume (SV) X heart rate (HR) - Oxygen Uptake and Lung Capacity- The oxygen uptake refers to the amount of oxygen the body uses per minute and is the maximum capacity of an individual's body to transport and utilise oxygen. Also known as VO2 max. This is the strongest indicator of an athlete's ability in endurance events. The oxygen uptake will improve as a result of training. The lung capacity of athletes undergoing training will remain the same as they were before.
- Haemoglobin level- The haemoglobin molecule is the substance that the oxygen molecule binds to for transportation around the body to working muscles and other body parts that required it for survival. It is found in the red blood cells. As the oxygen uptake increases with training, so does the haemoglobin content due to increased efficiency of the cardiorespiratory system.
- Muscle Hypertrophy- Muscle hypertrophy refers to an increase in the muscle size. As an immediate response to training, the muscle fibres increase in size as more fluid goes into the muscle. As a response to extended training, the muscles used will increase in size again as the fibres adapt to the training load and lead to an overall increase in muscle size.
- Effects of training on slow twitch fibres- The slow muscles are more efficient at using oxygen to generate more fuel (ADP) for continuous, extended muscle contractions over a long time. They fire slower than fast twitch fibres and can go for a long time before they fatigue. Therefore, slow twitch fibres are great at helping athletes run marathons and compete in long distance events.
- Effects of training on fast twitch fibres- As fast twitch fibres use anaerobic metabolism to create fuel, they are much better at generating short bursts of strength or speed than slower muscles. However they fatigue much faster. Fast twitch fibres generally produce the same amount of force per contraction as slow muscles. Having more fast twitch fibres can greatly assist sprinters or short burst athletes.