Training for My Second 10k

2 years ago I ran my first race — a 10k which took me 1h13m. Then I stopped running for about a year, and have recently decided to get back into it and train for a second 10k. I have a couple of questions:

(1) Is 1h10m a realistic goal for my next 10k, or is that too much?

I now got to the stage where I am running 3 times a week, 6–8 miles a week in total. I have about 12 weeks left until the race and although I plan to increase my mileage, I won't have time for a lot more than 3 sessions a week. I should also mention that I'm using more or less the same training plan as last time, but trying to do everything a bit faster.

(2) My current runs are all supposed to be easy runs (I'm going to introduce speed work a little later in training). I run them at about 13:10–13:20 min/mile. From the breathing and heart rate point of view this is very easy for me, but my legs are always very sore — even after one mile. (I don't think it's an injury — after I rest for a day or so, they are usually back in action.) Any suggestions on how to address this problem?

Answer by Dom:
Hi there — great to hear you're back at it and training for your second 10k. Both of your questions are very common ones, and I'm happy to tackle them properly because there's a lot more to unpack here than a quick reassurance.

I'll break this down as follows:

1. Is 1:10 realistic — and could you actually go faster?
2. How to add mileage safely in the 12 weeks you have
3. Why your legs are sore — and what to do about it
4. When to push through and when to back off

1. Is 1:10 Realistic — and Could You Actually Go Faster?

Yes — 1:10 is a perfectly realistic goal. But I'd actually encourage you to be a bit more ambitious than that, because based on what you've described, you may well be capable of more.

Here's why: you're already running three times a week and your cardiovascular system is clearly coping well — you said your breathing and heart rate are both very easy at your current pace. That suggests your aerobic engine is ahead of where your legs are right now. With 12 weeks of consistent training, especially if you add some mileage, you could genuinely surprise yourself on race day.

A goal of 1:10 represents roughly a 4% improvement on your 1:13. That's achievable, and with good execution you might find yourself running something closer to 1:07 or 1:08. I wouldn't aim for that specifically — aim for 1:10 and run your own race — but don't be surprised if you come in faster.

One thing I'd caution against: trying to do everything a bit faster this time around isn't always the right approach. Easy runs should still feel easy — genuinely easy. If you're pushing the pace on what should be recovery runs, you'll accumulate fatigue without the corresponding benefit. Consistency matters far more than pace in your day-to-day training.

2. How to Add Mileage Safely in the 12 Weeks You Have

At 6–8 miles per week across three sessions, your mileage is still on the lower side — and adding miles is the single most impactful thing you can do in the next 12 weeks. The key is doing it carefully.

I'd recommend following the 10% rule: don't increase your total weekly mileage by more than 10% from one week to the next. So if you're at 7 miles this week, go to around 7.5–8 next week, then 8.5–9 the week after. It sounds slow, but this gradual approach is how you add mileage without ending up injured.

For detailed guidance on doing this right, have a look at my increasing mileage safely page — it walks through exactly how to progress without overdoing it.

One specific goal I'd set for you: get your long run up to at least 6 miles — ideally 7 or 8 — before race day. Being able to cover close to the full race distance in training does two things. It gives you the endurance to complete 10k comfortably rather than just surviving it, and it gives you a lot of confidence on the start line. There's a big psychological difference between stepping up to a 10k having only run 4 miles at a time versus having done 7 or 8 miles in training.

With three sessions per week over 12 weeks, a structure I'd suggest is: one slightly longer easy run (your long run, building each week), one medium easy run, and one run that can stay shorter as your recovery session. Once you're a few weeks in and the mileage feels manageable, you can think about adding some light strides or easy fartlek at the end of a run — but there's no need to rush into speed work whilst your legs are still adapting.

For a more structured approach, have a look at my 10k Running Program for Beginners. It's technically aimed at first-timers, but given that you've had a year off, it's a very appropriate place to start — and following a structured programme removes a lot of the guesswork.

3. Why Your Legs Are Sore — and What's Actually Happening

This is such a common experience when returning to running after a break, and it catches a lot of people off guard — especially because, as you've noticed, your heart and lungs feel absolutely fine whilst your legs protest loudly.

Here's what's happening: your cardiovascular system adapts relatively quickly to training. Your heart and lungs are already keeping pace with the demands you're placing on them. But your muscles, tendons, ligaments, and connective tissue adapt much more slowly — they're playing catch-up. The soreness you feel is primarily muscular adaptation — specifically, delayed onset muscle soreness from the eccentric load of running (the portion of each stride where your muscles lengthen whilst under tension, particularly going downhill or absorbing impact).

Your connective tissue — the tendons and fascia around your calves, shins, and feet — takes even longer than muscle to remodel and strengthen. This is perfectly normal and not a sign that anything is wrong. It's simply your body doing the work of adapting to a new demand.

The fact that you recover within a day or so is genuinely reassuring. That's the right pattern for normal adaptation soreness — you stress the system, it recovers, it comes back slightly stronger. If the soreness were lasting three or four days, or getting progressively worse rather than better, that would warrant more attention.

4. When to Push Through and When to Back Off

I'd encourage you to keep running through this soreness — provided a few conditions are met. First, the discomfort should be diffuse and muscular rather than sharp or localised to a specific spot (which could indicate a stress fracture or tendon issue). Second, it should clear within 24–48 hours of a run. Third, it shouldn't be getting worse week over week.

If all three of those are true, you're experiencing normal adaptation and the right approach is simply to trust the process. The soreness will ease significantly over the coming weeks as your legs get used to the load. Most runners find that after four to six weeks of consistent training, the legs stop complaining as much — not because you've toughened up mentally, but because the physical adaptations have caught up.

Practically, a few things can help: make sure you're not starting your runs cold — a few minutes of brisk walking before you begin is genuinely useful. And keep your easy runs easy — if you're pushing the pace even slightly, you're adding extra muscular stress that slows down the adaptation process.

You're in a better position than you might think. You've rebuilt your consistency, your cardio is strong, and your legs are simply doing the work of catching up. Stick with the three sessions a week, build that mileage gradually, and I'd expect you to finish your second 10k feeling considerably better than your first — and quite possibly faster than 1:10 :)

Good luck with the training.

All the best,
Dominique

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