Sure, variety is the spice of life. But what if you want to keep life simple? What if there were just three rock-solid sessions that could underpin any running routine? Three universal, can’t-fail work-outs that could take you close to your potential, whatever your training or racing goals?

You guessed it: there are. Use the following three sessions as the bedrock of your weekly routine and you’ll be firing yourself up with speed, strength and endurance – the three key ingredients of strong, easy running.

Then add as many easy, conversation-paced recovery days as you want to, and bingo: you have a foolproof, powerfully effective training week. All you have to avoid then is doing any of the key sessions on consecutive days, as you will need time to recover. The beauty of the sessions is that they can form the basis of everything from 5K training to (with a little tweaking of the long run) a full marathon build-up. They’ll also keep you ticking over without getting stale in the times when you have no race goals. The five-minute repetitions are lengthy enough to sharpen your speed over long distances, but sufficiently pacy to give you powerful acceleration in the final mile of a 5K. The 90-minute run will provide a quality endurance session without leaving non-marathoners exhausted. And the flexible hard-and-easy session that we call hilly fartlek can tailor your week towards whatever your race goal is – and crank up your leg strength and cardiovascular power into the bargain.

Best of all, the sessions embody what running is all about. Letting your mind wander on gentle Sunday outings. The glow of exhausted achievement on running your final repetition as fast as your first. The spontaneous pleasure of a fartlek session with a friend.

We’re not saying that you should do these sessions week-in, week-out, month after month. It’d be dull, for a start. But take time to learn how to get the most from them, and you’ll keep coming back to them like old reliable friends.

5-minute repetitions

Why? You’ll get fitter and faster by breaking up fast running with rest intervals, because it enables you to do more high-quality running than only running flat out. After just a few weeks of speedwork, your maximal oxygen uptake will rise, and your running economy will improve. Run speedwork at the right pace (see below) and your lactate threshold will rise, too, which will delay the point at which your legs start to feel heavy during brisk running. All of this not only guarantees you faster race times; it will make ordinary training feel much easier, too.

How? Find a clear circuit – ideally on smooth grass or a track – that takes about five minutes at your realistic goal 5K race pace. (A constant distance is more important than an exact time, so if you work out on a track, for example, use three laps.)

After jogging easily for 10 minutes to warm up, and then stretching lightly, run one circuit at 5K pace, followed by four minutes of very light jogging to recover. If you’re new to speedwork, repeat this twice more, then jog easily for 10 more minutes to help minimise soreness the next day. If you’re experienced, aim for four to six repetitions in total.

In all cases, aim to run evenly, so that you finish the last repetition as strongly as the first, without feeling that you could do more repetitions after the last one. (If you don’t know what your 5K pace is, this is a particularly good rule of thumb to follow.)

For variety…

1. Over a number of weeks, gradually reduce the length of your recoveries, while keeping the speed of your efforts consistent. This will better adapt you to race conditions. If you’re aiming for a 5K, you’ll be ready to tackle a new PB at your goal pace when you can complete sessions evenly with just two-minute recoveries.
2. Work slightly slower than 10K pace (or about 20 seconds per repetition slower than before), with just two- to three-minute recoveries. This will raise your lactate threshold and delay fatigue.
3. Do sets – for example, two repetitions with a two-minute recovery between them; then a five-minute recovery, then two more repetitions with a two-minute recovery. This gives you some of the race-specific benefit of short recoveries, even if you’re not at peak fitness.

90-minute long run

Why? Long runs are excellent fat-burners (the average 10-stone runner burns 100 calories per mile, so 10 miles eats through a whopping 1000 calories). They also help to teach you the valuable art of conserving your energy through sensible pacing, and serve as a great confidence-builder when it comes to racing. Physiologically, long runs increase the number of mitochondria and capillaries in your muscles, which boosts their oxygen-carrying capacity – in other words, they’ll turn you into someone who can run faster for longer. They also teach your central nervous system to delay feelings of fatigue, and teach your body to conserve carbohydrate reserves in favour of fat, both factors that will keep you strong at the end of a long race. Need any more reasons?

There’s no magic length for a long run – it depends on your goals. But 90 minutes is long enough to kick in the increased fat- burning response that occurs after about eight or nine miles, and fire up some of your other physiological responses to fatigue.

How? Go slowly – that means conversation-pace, about 65 per cent of your working heart rate, or a minute per mile slower than your target marathon pace. Your legs should feel pleasantly used, not absolutely wasted, after your run, which means that you should be concentrating on comfortable time on your feet. That’s particularly true if you’re a beginner, in which case you should build up your long runs by no more than 10 minutes a week, and not be afraid to take one-minute walk breaks every mile or so. Ideally, run on trails, grass and woodland – soft surfaces which will keep your legs freshest and least at risk of injury.

For variety…

1. Once you become more experienced and durable as a runner, you can add some faster segments. These not only make you better at running on tired legs; they break up your run and make it more enjoyable.
2. Ninety minutes is great for all-round fitness. But if you’re training purely to be the best 5K runner you can, 60-75 minutes is ample for a long run. For marathon training, you need to build up to around three hours or more, and, ideally, two hours or more for a half.
3. From time to time, forget your targets, pull your trail shoes on and head out with a map to explore new footpaths and tracks. When you’re clambering over stiles and discovering places you didn’t know existed, you’ll forget that you’re even running.

Hilly fartlek

Why? Even though it means ‘speed play’ in its original Swedish, this session of fast and slow bursts in a normal-length run can be the most effective work-out of your week. Like structured speedwork, it’s a super way of improving your strength, power, economy and VO2max, but in a more rounded – and fun – way. If you add some good, strengthening hill-climbs, it’s a total all-in-one session.

How? Choose what, for you, is a normal-length route – say one that’s 35-50 minutes long. After 10 minutes of easy running, simply start to throw in some fast bursts – anything from 20 seconds to two minutes. You decide exactly how fast they should be, and how fast and long the recoveries should be. There are no rules – just try to discover how to push your body successfully in response to different pressures. Be specific about the length of each effort, so that you don’t tail off halfway through it. Say, for example, ‘I’m going to run to that tree or that lamppost, or for 30 breaths, or 50 strides.’

For variety…

1. The great thing about fartlek is that every session can be a variation. That’s what keeps it so fresh. But do try to include hills in your route as often as possible – they’re a tremendous fitness booster, and yet they don’t batter your legs like hard sessions on the flat can.
2. Take a friend! You’ll be far less inclined to be lazy when there are two (or more) of you. Take it in turns to call out the length and speed of the next effort, and you’ll find that the session will fly by.
3. Lope... That is, take the run fairly easily and use the efforts simply as a way of stretching your legs out. Don’t raise your heart rate too high or build up lactic acid in your legs. This is an ideal session to do on the day before a race.