I found an interview with renowned coach Andrew Kastor on improving your best time for 5K. Below are some of his suggestions. I’ve also added my own personal view based on experience.
Add Speedwork: If you want to run a 5K faster, you have to practice running faster. Andrew suggests adding (4 to 6) 80 metre sprints to a training session. Perform these sprints at the end of a steady run. If you’re not used to sprinting, you may have to start with shorter sprints and build up.
I prefer a session of short intervals with a short recovery. I sprint for 20 -30 seconds, and then jog up to a minute for recovery, before repeating the process (usually 8-10 intervals). I train like this once or twice a week. The key is to find what works for you.
Strength Training: Running alone won’t increase your speed. You need to strengthen the muscles that make you move so your actions will be more powerful and more efficient. Incorporate strength training moves which target your shins, calves, quads, glutes and core.
I agree with this. It will help prevent loss of form at that point in the race when you start feeling very fatigued. But why stop there? One of the worst areas for me when I’m fatigued (in a race) is my shoulders. For this reason, I work on them, chest and arms as well.
Become Familiar with the Route: Knowing the course in advance will give you confidence…
Yes. You’re better mentally prepared if you already know the good/ bad stretches of the course. Also, run on the inside of the track/ path/ road where possible. There’s no point running further than you have too.
ON RACE DAY
Warm Up: Brisk walk or jog 25 minutes before the start. This not only helps to prevent injury; your muscles will also be ready to go once the race begins.
Absolutely: at least 15 minutes for me. If I’m not properly warmed up, I can forget a fast time.
Start out Strong: research shows that approaching the first part of the race at a slightly faster than your normal pace will actually result in a shorter overall time.
This is something I discovered for myself last summer. I have to start at a pace slightly faster than I’m comfortable with. I would rather grow into the race by picking up pace once I’m getting used to the demands on my cardiovascular system. There’s also the worry that by starting too fast, you will pay for it later. It’s a fine line you are better able to judge once you’ve raced a few times, but my best times have all come from starting faster than I would like.