Best Way to Train to Reduce 1.5 Mile Time by 1 Minute

I want to be a PTI [physical training instructor] in the army. I'm in the army already but to do this I need to run a mile and a half in under 9:30. I can do it in about 10:30.

What's the best training to do so I can get my time under 9:30 and how far should I run every day to be able to do this? Also, will changing my diet to become more healthy help me in getting this time and run fast?

Thanks

– Jenny, UK

Answer by Dom:
Hi Jenny, good on you for going after the PTI role, and you've asked exactly the right questions. You haven't told me how often you currently train or how long you've been running, so I'll need to stay somewhat general, but I'll give you as much specific guidance as I can. A one-minute improvement on 1.5 miles is achievable. It takes consistent training over several months, not weeks. I'd break my answer down like this:

1. Run more miles, mostly easy: the foundation you can't skip
2. Speed variety: three types of session that will make you faster
3. Diet: eat well, cut alcohol and lose a few pounds if you need to

Run More Miles, Mostly Easy

Let me tell you the mistake I see most often with people preparing for the 1.5-mile test. They run three or four times a week, all at about the same pace, and wonder why they're not getting faster. The answer is almost always that they're not running enough total mileage, and most of what they do run is too hard.

The first step is to add one more running day. If you're currently running three times a week, make it four. If it's four, consider five. Most of that running should be easy, a pace where you could hold a conversation comfortably. Easy running builds your aerobic base (the fitness that keeps you going at an easy effort), which underpins everything else.

Your long run, once a week, should gradually extend. Work up to 5–6 miles at easy pace. It sounds counterintuitive to run 6 miles to prepare for a 1.5-mile test, but it works. The endurance you build on long easy runs translates directly into being able to sustain your race pace without fading. Build your mileage gradually: don't jump more than 10% per week. See the Increasing Mileage Safely page for practical guidelines on doing this without getting injured.

For reference: to run 1.5 miles in 9:30, you need to hold 6:20 per mile. Your current pace of 10:30 is about 7:00 per mile. You need to find 40 seconds per mile. That doesn't happen through willpower on test day; it happens through months of progressive training.

Speed Variety: Three Sessions That Will Make You Faster

Once you have a solid base, which means being able to run 4–5 miles comfortably, it's time to add faster running. Each type of speed work stresses a different energy system, and you need all three in your program.

Interval running (repeated shorter fast runs with easy recovery in between) is the most direct preparation. One session per week: 6 × 400m, each at around 1:33–1:35. That's roughly 6:15 to 6:25 per mile, right around your goal race pace, with 90 seconds of easy jogging between each repetition. This trains your legs and lungs to hold goal pace comfortably under repeated effort, so race pace starts to feel manageable rather than punishing. Check out the Interval Running page for more detail on how to structure these sessions.

Tempo running is equally important. Once a week, after a warm-up, run for 20 minutes at a comfortably hard effort, faster than easy but not gasping. This should feel like a 7 out of 10 effort. It trains your lactate threshold (the effort level where your legs start to burn), which directly improves the pace you can sustain over 1.5 miles. Tempo running is steady work, and it is one of the best things you can do for a 1.5 mile test.

Goal-pace running is what ties it together. Once every two weeks, include goal-pace intervals in a session, for example 2 × 0.75 miles, each in 4:45 (that is 6:20 per mile, your 9:30 goal pace), with 2 minutes rest between. This teaches your body what race pace feels like when you're tired, not when you're fresh.

Once a month, do a full 1.5-mile time trial (a full-effort practice run) to check your progress. If you can include some strides at the end of easy runs (4 × 20 seconds of fast, relaxed running), those help too. The mix of all these (long easy runs, intervals, tempo and goal-pace work) is what will get you to 9:30.

Diet: Eat Well, Cut Alcohol, Lose a Few Pounds

Yes, Jenny, diet will help, but not through anything complicated. Here is what matters.

If you are carrying extra weight, losing even 2–3 kilograms (about 4–7 pounds) will make a noticeable difference to your 1.5-mile time. Running carries your bodyweight over every meter of the course. Less weight means less effort for the same pace. See the Runner's Diet page for more on eating well as a runner.

Even if weight is not a factor, the quality of what you eat affects your training. Cut out alcohol during your preparation, because it disrupts sleep, hampers recovery, and adds empty calories. Cut back on junk food and processed snacks. Eat proper meals with enough protein (chicken, fish, eggs, pulses) to support the muscle recovery your body needs when you're running four or five days a week.

That's genuinely it. You don't need a complicated plan, you need consistency. Eat well, sleep well, train hard, and trust the process. With the right mix of mileage, speed work, and sensible eating, sub-9:30 is well within your reach.

If you'd like the mileage and session mix worked out around your own current time and test date, I built AceTheTest to build a day-by-day plan around exactly that. It's free to start.

If you would like a second set of workouts aimed at getting under 10 minutes, see workouts for a sub-10 minute target. Your next step: this week, add one more easy running day and book your first interval session of 6 × 400m. Good luck with the PTI ambition, Jenny, it's a role worth working hard for.
All the best,
Dom

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