If you want to improve your running performance, you need to build your speed endurance. And the way that you will build your speed endurance is by running with more intensity for longer.
To achieve this, you need to build up your cardiovascular strength, which means you need to be able to train your body to run for a certain amount of time at a certain heart rate.
The more conditioned your body is to this, the less likely your body is to decelerate when running.
To excel, you need to train your body to perform at 85-95% of your maximum heart rate over the distance that you want to run.
How can you calculate your heart rate?
You can use the following formula.
220 – (Your age) = Maximum heart rate per minute.
If you are 25 years old, then your maximum heart rate will be 195 bpm
To perform at 85-95% intensity, you will need to run with a heart rate of 165-185.75bpm.
If you are 35 years old, your maximum heart rate will be 185 bpm.
To perform at 85-95% intensity, you will need to run with a heart rate of 157.25-175.75bpm.
This is just an estimate, but it is a good model to work with.
You can see an example of a running heart rate zone below.
How can you improve your heart rate intensity?
You will need to do a combination of interval, stamina, and fartlek training for the distance that you want to run.
If you are a sprinter, you should be building your strength-endurance like a 400m runner so you can always finish strong in the 100m or 200m. This will see you do interval sprint training of 300-600m at 85-95% intensity with a few minutes recovery.
For middle and long-distance runners, fartlek training and intervals will help to train your body to raise and lower the intensity in different running bursts.