SPEED WORK 101: INTERVALS, TEMPO RUNS, AND HILL REPEATS EXPLAINED

If you have spent the last few months building an easy-running habit, you are ready for the next step. Speed work is the part of training that asks your legs to go faster than comfortable — and a little of it goes a long way.

This is your introduction to the three staples: intervals, tempo runs and hill repeats. You will see what each one actually improves, how a single session looks in practice, and how to add one speed day a week without upsetting the easy running that got you here.

What is speed work?

Speed work is any running that is faster than your easy, conversational pace, done in short, structured doses with recovery built in. It teaches your body to run faster rather than simply longer: your heart moves more blood with each beat, your legs turn over more quickly, and your stride becomes more economical at every pace.

That last part is worth remembering. Speed work does not only make your fast running faster — it makes your easy running easier, because an efficient stride costs you less at any speed.

Most of your week still stays easy. The speed session is the small, sharp part of the plan. The easy miles are what let you absorb it.

This article assumes you already have a base of steady running behind you. If you are still building one, stay with it a little longer — speed work lands much more kindly on a body that already handles 20 to 30 minutes of continuous running.

What do interval workouts improve?

Intervals are short, hard repeats separated by easy jogging. They improve your top-end speed and your running economy — how much effort a given pace costs you — and they teach you what fast feels like, so it stops being intimidating.

A simple interval session looks like this: after a 10-minute easy jog and a couple of 20-second strides, run six 1-minute efforts at a hard but controlled pace, jogging easily for 2 minutes between each one. Finish with 5 to 10 minutes of easy running. That is about six minutes of hard work tucked inside a 45-minute run.

The effort is the part people get wrong. Run the first repeat as though you have five more to go. If the last one feels much harder than the first, you started too fast — next time ease off and keep every repeat even.

Intervals are the best place to start if you are unsure. A minute is short enough that you can hold good form, and the recovery jogs give you time to catch your breath and reset.

What is a tempo run and what does it improve?

A tempo run is a sustained effort at a comfortably hard pace — roughly the pace you could hold for about an hour, where you can speak a few words but not a full sentence. It improves your ability to hold a faster pace for longer, and it builds the rhythm you will want on race day.

Where intervals train your top speed, tempo runs train your staying power at speed. The classic version: 10 minutes easy, then 20 minutes at tempo, then 10 minutes easy to finish. If 20 unbroken minutes feels like too much, break it into three 6-minute blocks with a minute of easy running between them and build up from there.

Finding your tempo pace without a lab

Warm up for 10 minutes, then lift the pace gently for a few minutes. If you can say four or five words at a time, you are close. If you are gasping out single words, back off. If you can chat normally, speed up. Tempo should feel purposeful, never desperate.

Why do hill repeats make you stronger?

Hill repeats are short, hard climbs with an easy jog or walk back down. They build leg strength and power because you are pushing against gravity — which means you can load your muscles hard with far less of the pounding that comes with running fast on the flat.

That makes hills a good first hard session for many runners. The effort is high but the impact is gentler, and the walk back down is recovery built into the workout.

Start with a hill that takes 45 to 60 seconds to climb. Run up at a strong, even effort, jog or walk down, and repeat six times. Keep your steps short and quick, look a few metres ahead of you, and resist sprinting the first climb.

How do you add speed work safely?

Add one speed session a week and keep everything else easy. That single change is enough to make a real difference, and it is the version your body is most likely to absorb without complaint. Here is how to make the first month work:

1. One hard session a week. Running three or four times a week? One of those is the hard one; the rest stay genuinely easy. If in doubt, keep the easy runs slower than feels necessary — that is their job.
2. Warm up and cool down. Ten minutes of easy running before, five to ten after. Give yourself the full warm-up; hard running on cold legs rarely ends well.
3. Leave a day either side. Put an easy or rest day after your speed session. Two hard days back to back is where beginner training most often goes wrong.
4. Add a repeat before you add speed. When a session starts to feel comfortable, make it longer — one more minute, one more hill — rather than faster.
5. Rotate the type. Intervals one week, tempo the next, hills the week after, then start again. Each one trains something slightly different, and rotating spreads the load.
6. Stop for sharp pain. Feeling tired is normal and expected. Sharp pain in one spot, or a limp that changes your stride, is not — stop, let it settle, and come back easier.

What does a week of speed work look like?

Keeping the shape simple is the whole trick. Rotating the session each week keeps it interesting and spreads the effort across slightly different muscles:

• Run 1 — easy, 30 minutes. Conversational the whole way.
• Run 2 — speed session, 45 minutes. Warm-up, one of the sessions above, cool-down.
• Run 3 — easy, 35 to 40 minutes. Same easy effort, a little longer.

Treat that as the shape of the week rather than a set plan, and build it around the days that actually fit your life.

How do you know it is working?

You will notice it before you can measure it. A stretch you used to run at tempo pace starts to feel conversational. The recovery jog between intervals feels like it arrives sooner. A hill that had you gasping in week one feels noticeably shorter by week four.

Give it four to six weeks before you judge anything. One fast day does not mean you are fitter, and one sluggish day does not mean it is not working — your easy running is still doing most of the heavy lifting underneath.

Speed work is not about proving anything. It is a weekly appointment where you ask your legs for a little more than usual, in a dose small enough that you can keep the rest of your running relaxed. Pick one session, keep it honest, and let it grow from there.

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