Your body is composed of various systems that all have different functions, however they all have to work together to work properly. As an athlete, the cardiorespiratory, muscular, and skeletal systems are the most important ones. When comparing and average runner to an elite runner there are considerable differences in these three systems. The cardiorespiratory system has the biggest difference, mainly in the heart, with its capacity to pump more blood through the entire body. The more the heart pumps blood through the entire system the more oxygen is delivered to all the muscles resulting in the production of more ATP.
For any individual, the maximal heart rate and maximal stroke volume determine how much blood the heart can pump (i.e., the maximal cardiac output).
Cardiac Output (Amount of blood the heart can pump in a minute) = Heart Rate (Number of bits per minute) x Stroke Volume (Amount of blood per beat)
When taking into effect the performance of different runners the biggest difference is the maximal stroke volume. The main reason for this is the heart rate is solely based on age. Take for example you have two runners the exact same age one is in better shape then other. They will both have they both will have the same maximal heart rate. The biggest difference between these to runners is in the person that is more fit their maximal stroke volume is greater then the one not in as good of shape.
Endurance Training & Cardiac Output
The reason elite runners can average a pace of four minute-per-kilometer is because they have a higher level of volume and cardiac output. You can increase your maximal stroke volume and cardiac output by endurance training; this will result in better performance during your aerobic exercises. Some examples of endurance training would be swimming, running, even bicycling. Doing exercises such as these will increase your volume and cardiac output close to 20-30% alone. Elite runners get a good majority of there athleticism from genetics and the everyday average runner can be just as good with proper training to increase the hearts ability to pump more significant blood to the heart.
Your heart is just like any other muscle in your body the harder you train, the harder it works. With time just like you other muscles, it grows and adapts to this change growing stronger and working harder. This is because the harder and faster you train the faster the heart has to pump blood, the faster and more often your heart has to do this it gets better and better each time
Effects of training
There are four things the cardiorespiratory and muscular system increase from endurance training.
- Increase in overall capacity to perform endurance exercise.
- Increase maximal cardiac output, stroke volume, and VO2max.
- Increase in stroke volume and decrease in heart rate at any sub maximal work effort.
- Increase in stroke volume and decrease in heart rate at rest
You should see a decrease in your resting heart rate and the heart rate at any sub maximal running speed. Increasing your pace will result in your heart rate to stay at a specific rate.