Do not practice speed running before spending a few months preparing for it! If you are over 35 years old, the minimum preparation time is 1 year (one year!).
Running fast starts with a lot of slow, careful running.
If you skip the slow running and go straight to fast speeds, you could hurt your bones and joints. We know because it's happened to us. It's better to start slow and keep running for a long time.
Running fast is different from regular running. The muscles work in a different way, and even the way your feet touch the ground changes.
At the end of each running exercise, slow down to 80% of your speed. This helps prevent injuries, especially to your knees. Also, only sprint on flat ground, not uphill or downhill.
Speed game (Fartlek):
Pick an object 20 to 100 meters away and run fast to it. After you pass it, slow down until your heartbeat returns to normal. You can do this exercise multiple times during your run, but keep it to 20-50 meters for the first two months.
If your plan says to do this for 5 minutes, start with just two or three times. It's important to learn how to get your heartbeat back to normal, and that takes time and proper breathing.
Don't do speed running until you're ready for it. It's good for building strength in your legs, but only if you're fit enough.
Don't run fast with a backpack or extra weight. This is bad for you. If you're overweight, lose some weight before trying more advanced running.
For a tempo run, start slow. After a third of the time, speed up until your heartbeat is 85%-90% of its maximum. For the last third, slow down again. In a one-hour run, make sure only 20 minutes are at the faster "tempo" speed.
Interval runs are tough and should only be done if you're advanced and well-prepared. This means you've spent months strengthening your legs and heart. Running too hard in intervals can make you tired, cause pain, and lead to mistakes that might hurt you.
In interval running, you pick a distance to run fast, then slow down for a bit, but not long enough to fully rest. Then you run the fast distance again.
For marathon training, people usually run fast for 800-1000 meters and then slow down for 200-300 meters. Most people run fast for 200-300 meters and then slow down for the same distance. This is a common distance in situations where you might have to run fast in a city.