Want to Improve My 5k Race Speed

Hello, I am 16 years old and I run cross-country and track for my high school. My PRs are: 400m = 58.5 / 800m = 2:12 / 1600m = 5:05 / 5k = 18:24. I’ve been working hard all summer on a goal of 17:15 for a 5k, trying to run 5:40–5:45 mile splits. But I end up averaging around 6:10–6:15 per mile. Could you give me some workouts to help get my splits down?

— Paul, Jackson, TN

Answer by Dom:

Hi Paul,

Fantastic to hear from you. A goal of 17:15 from an 18:24 personal best is ambitious—and you have every reason to believe you can get there. Let me show you why, and then I will tell you exactly what to do about it.

Here is what we will cover:

1. The race conversion calculator — some analysis
2. The big irony of running — the easy run
3. What your summer should look like
4. Other tips to get faster
5. A note on patience

The Race Conversion Calculator — Some Analysis

I put your PRs into my Race Conversion Calculator. Here is what came back:

• Your 800m of 2:12 predicts a 1600m of about 4:35 — your actual is 5:05.
• That same 800m predicts a 5k of roughly 15:20 — your actual is 18:24.
• Your 1600m of 5:05 predicts a 5k of around 17:00 — your actual is 18:24.

Read that again. Your 800m speed predicts a 5k of 15:20. You are actually running 18:24. That is a gap of over three minutes—and it is not a speed problem. You have world-class 800m speed relative to your 5k. The gap tells us something very specific: you have the engine, but not the fuel tank to run on it for 3.1 miles. Your aerobic base is lagging behind your raw speed.

The good news is that this is the most fixable problem in running. A stamina deficit responds directly to consistent, progressive easy mileage. Your goal of 17:15 is within reach—and your 1600m of 5:05 already predicts you are close. You just need the aerobic base to back it up.

The Big Irony of Running — The Easy Run

You asked me for workouts to make your splits faster. I understand why—it feels logical. Run faster in training, race faster in autumn. But based on your numbers, that is not what you need right now. Here is the twist: you need to be running slower and longer. The big irony of running is that you go slow to go fast.

When you look at elite 5k runners, two things stand out. They cover a huge amount of mileage every week, and most of that mileage is done at a surprisingly relaxed pace—7:30, 8:00, even 8:30 per mile. This easy running builds the aerobic base that lets them sustain fast pace on race day. Without it, even the most naturally gifted athlete will fade in the back half of a 5k.

For you, Paul, easy pace right now is around 7:30–8:00 per mile. That probably feels painfully slow. It is supposed to. Easy running should feel almost embarrassingly relaxed—a full conversation, no gasping. If you are breathing hard, you are running too fast.

The long run is the single most important session in your week. Build it from 5–6 miles toward 10–13 miles over the course of the summer. A runner who can comfortably handle 10 miles in training has a completely different aerobic foundation than one who maxes out at 5. Check out the base building page for more on this approach.

What Your Summer Should Look Like

Here is a practical three-phase summer plan. Wherever you are right now in your weekly mileage, do not jump ahead—build no more than 10% extra mileage per week, and take a slightly easier week every three to four weeks to let your body absorb the training.

Phase 1: Weeks 1–5 — Base Building
Daily easy runs at 7:30–8:00 per mile. Long run builds from 5 miles to 9 miles over these five weeks. No hard sessions yet. The only exception: add four to six strides (20-second accelerations at the end of a couple of easy runs per week) to keep your legs sharp without adding meaningful training stress. That is it. Most of your running is easy. This is the foundation everything else sits on.

Phase 2: Weeks 6–10 — Quality Work
Keep two or three easy runs per week, including your long run (now 9–12 miles). Add one tempo session per week: start at 20 minutes at threshold effort (roughly 6:15–6:20 per mile for you right now—comfortably hard, not a race), and build toward 30 minutes by week 10. Add one interval session per week: 800m–1000m repeats at 5k effort with equal time jogging recovery. Start with four repeats and build to six or seven.

Phase 3: Weeks 11–13 (or until your season starts) — Sharpening
Your goal pace for 17:15 is 5:33 per mile, which is 83 seconds per 400m. Now is the time to practise it. One session per week: 10–12 × 400m at 83 seconds with 60–90 seconds easy jog recovery. Keep the other runs short and easy. Reduce total mileage slightly. You are not building fitness in this phase—you are freshening up and teaching your legs to run the target pace automatically.

Other Tips to Get Faster

Strength Training
Adding strength training—whether bodyweight exercises, gym work, or both—improves your running economy and helps you resist fatigue in the final kilometre of a race. It also makes you more resilient against the niggles that derail high school runners mid-season. See the Strength Training for Runners page for ideas.

Speed Workouts
Once Phase 2 begins, you can start adding structured fast running. See the Running Workouts page for a full summary of session types—fartlek, tempo, intervals, and more.

Rest and Recovery
Rest is not optional. It is part of the training. Your body gets fitter during recovery, not during the run itself. Allow at least one full rest day per week and treat sleep as seriously as your sessions.

A Note on Patience

I want to be honest with you, Paul, because I think you deserve a straight answer. The easy miles will feel pointless when your goal is to run 5:40 pace. You will wonder whether all that slow jogging is actually doing anything. I understand that feeling completely.

But here is what I know: the athletes who build the most aerobic base over the summer are the ones who run 17:15—and sometimes 16:50—when the cross-country season arrives in October. The connection is direct and well-established. Base building is not a detour from your goal. It is the most direct route to it.

The months of July and August spent running easy will feel like they belong to a different sport. Come September and October, you will understand exactly what they were for. Trust the process.

Your speed is already there. Now build the engine to carry it. You can absolutely do this.

Kind regards,

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