Marathon des Sables 12 Week Plan by Andy Mouncey

Last updated: 23-Aug-18

By Andy Mouncey

Marathon des Sables is one of the biggest ultra events in the world. For many, it is a dream to take on and complete the challenge. At RunUltra, we have commissioned top coach Andy Mouncey to come up with a training plan for the Marathon des Sables.

Who Is Andy Mouncey?

Andy signed off 17 years in triathlon setting record stage times for the Enduroman Arch To Arc Challenge in 2003: A 300 mile solo triathlon linking London and Paris via an English Channel swim. Since then he’s been getting his kicks ultra running and has placed 2nd twice at the UK’s premier trail 100 miler Montane Lakeland 100. He has been coaching and speaking professionally since 2000 working with a range of clients in sport, education, business and everyday life – and that has included runners attempting MdS. He is a published author, married and lives with his family in the north of England.

Health Warning

I would never give this plan unedited to one of my clients. I would use the framework and some of the sessions as appropriate for that person. Coaching is a process that should be made personal to the client – and part of the skill of a coach is to do just that so the client (a runner in this case) gets a plan that is right for them.

So if you were a really strong climber for instance, out would go the power climbing sessions and in would come something else.

Follow this plan blindly and you will be asking for trouble.

However, adopt a learning mindset and you will be better able to take the principles and make them fit your goals, training history and time available.

And if you want a plan that’s really right for you contact me at [email protected] or +44 (0) 7799 063115.

Three Principles That Keep It Simple

It’s easy to over-think this ultra running stage race stuff. There’s a lot going on and there’s a lot of time it’s all going on in. Easy then to lose sight of the big picture – so here are three things to build into your cunning plan that will help you.

1. Confidence Is The Currency

Your training should build confidence – it’s that simple. The best training for you is stuff that builds your confidence. Only you know what that is. I’m assuming no-one is paying you to do this thing so there has to be some fun in it for you somewhere. Do stuff you enjoy and stuff that builds your confidence and you’ll be just fine.

2. Start At The End

Plan with the goal in mind and the specific nature/crux of the challenge e.g.:

  • It’ll be hot so your preparation needs to reflect this.
  • There’ll be a ton of people around so you need to get used to moving and thinking in a crowd.
  • The longest stage comes at the end of the week so going into a big session already tired will help you get your head round that.

3. Put Your Downtime In First

The adaptations and the improvement come when we take our foot off the gas which means that the recovery time is arguably the most important part of your plan. Put this in first and guard it zealously. Missed a few sessions and tempted to try catch up in a rest week? Don’t even think about it.

Your Key Milestones: Rest & Test Week No 4, 8, 10

The Rest (from running)

  • Bike steady.
  • Hike brisk-fast keeping off the big hills.
  • Swim inc backstroke and kicking on back arms extended with/out fins.

The Test

Your readiness for MdS in this plan is based on three key measures:

  1. Your ability to complete an outing, take partial rest – then do it all again (mental toughness, recovery & personal organization).
  2. Your ability to complete time on your feet with minimal fuel (internal economy).
  3. Your ability to operate and still think clearly with raised body temperature (heat tolerance).

Three key workouts will test your progress on these measures:

  1. Back To Back (B2B)
  2. Depletion Outings
  3. Overdressed Runs

Test Week Workout Progression Summary

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Plan Summary

Week 1-4 Getting Ready (distances are in miles)

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Week 5-8 Really Running

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Week 9-12 Putting It Together

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Session Notes


Ultra running requires that you can maintain an upright a body position as possible for extended periods of time (often wearing a backpack) while moving over varied and challenging terrain. That means torso strength and that means full-body conditioning.

Your key exercises therefore should have you working in an upright and fully extended position e.g.:

  • Deadlift
  • Front squat
  • Cleans
  • Lunge
  • Kettlebell swings

You will notice no mention of ‘the plank’ exercise. Planks have their place – and that’s not here…

Of course you can do some of this on your own but if you are attempting the Olympic lifts (squats, deadlift, cleans) for the first time you will need qualified supervision. That means a strength-conditioning coach or a personal trainer who has Olympic lifting accreditation.

You don’t need to be down the gym three times a week either: a smart 10min pre or post run 3-5 times a week can be transformational.

Done properly you will get stronger without bulking. How strong do you need to be?

Good question: You just need to be strong enough to do the job – anything else is just chasing stats in the gym.

Depletion Outings

This is where you train your system to operate on its (almost limitless) internal fuel stores as opposed to relying on you shoveling in sugar and carbs.

Time On Feet (TOF) during which you deliberately limit/deprive yourself of fuel – though you should always carry supplies in case you have a serious wobble.

Hone this ability and you cut your fuel needs – and therefore weight and faff factor – right down.

Doing this right is a project in itself and in my experience most people need more than 12 weeks to do build up safely to a half day outing.

You will find you need to slow right down and use a combination of run-walk to avoid the dreaded bonk. Pre-breakfast outings enhance the effect.

Power Hike

Most of you will be walking the hills and a fast and efficient hike is often way easier to maintain than a run.

This session is where you get out on the hills (or stairs) and hike fast with a heavy pack and can be done repeats or a single long ascent.

You need to be progressing to a very heavy pack – 30-50% bodyweight: You should be able to lift it onto your back – just- and still maintain upright posture when hiking. You will find chest strap, boots and poles essential in the early stages.

Descending safely with a pack this heavy needs skill and caution in order to avoid injury and horrendous DOMS.

If your hiking is average and your climbing is weak this is the session for you – you may only be able to handle 10-15 min at a time to start with and nowhere near the target load but that’s OK: Start where you need to start and build.

Done well, this maybe the most intense session you will do – and you should expect to be sore afterwards.


If you’re coming out of a northern hemisphere winter then April in the desert can be a big shock. Build confidence in your ability to handle the heat by allocating some of your runs: ‘Over-dressed.’

The budget version is to go all Rocky Balboa and head out with lots of layers to a point of being ridiculously overdressed. Build up duration and layers as you would with any progression. Or you can sit on a stationary cycle with the heat turned up – or if you have time and money to burn you can put a treadmill into your spare room, close the windows, line the inside with plastic sheeting and turn on the free-standing burners. ‘Bet there’s a Youtube for that…

Out & Back Runs

This is where you practice pace control by making the return trip faster than the outward one.

Take a break at the turnaround to start with – say 5mins.

Progress by building duration, reducing the break and increasing the pace of the outward leg.

Experienced athletes will do the first leg building to near threshold, turn round on a minute, and come back 30 seconds faster over 30 minutes. You need to build towards that and that may mean starting at 20-5-20 minutes.

Bike Strength Ride

Stay seated and still on the saddle using a big gear so you are pedaling with a slow cadence – almost muscling the pedals over.

If you are an inexperienced cyclist then start cautiously adding e.g. 2-3 x 5min efforts into a ride with only a slightly lower than normal cadence as too much of this too soon can cause knee pain.

Progress so that 50-75% of the ride is big gear-slow cadence riding.

Cadence Run

A steady continuous run broken every 5min by 30sec at your target cadence.

The benchmark is 90 paces/30 seconds: You should feel light and brisk on your feet – that might be 80-85 paces for you. It helps to use a countdown timer function on a watch.

Progress by increasing the frequency of the 30 second breaks then go to 60, 90 seconds – keeping count per 30 seconds.

Tempo Run

Pick a route on/off road that’s not too technical hilly so that you can maintain a constant pace of around 80-85% heart rate or 8/10 effort. You should still be able to talk but the sentences will be short and you will need to pause to gather your breath. You will have to be on-task for these: Throttle back on any climbs and speed up on descents to keep the effort constant.

Speed Hike

Done on flat or undulating terrain with no pack or very lightweight, with option for boots and poles – your aim is to cover the ground quickly and efficiently.

If you don’t have a gym then there are still options – more details in my book ‘So You Want To Run An Ultra’.

And if you want a plan that’s really right for you contact me at [email protected] or +44 (0) 7799 063115.

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Entry Fee
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Date Range

Global - Virtual


A virtual race which can be run at any time shown on the dates shown, on any type of terrain in any country.

Suitable for

For runners from beginners to experienced as you choose your own course and challenge based on the guidelines and options set by the virtual race organiser.

Endurance - Multi-activity


An ultra distance race including at least two of the following activities such as running, swimming, cycling, kayaking, skiing and climbing. It may also include different climatic conditions (eg ice, snow, humidity, cold water, mud or heat).

Suitable for

Experienced multi-skilled athletes who have trained for the different activities included in this event. Admission to these races may be subject to receipt of a recent medical examination certificate. Check with the race organiser regarding entry requirements and any specialist equipment required such as a wetsuit, skis or a mountain bike.



Increase of up to 2000 metres with very challenging climatic conditions (e.g. ice, snow, humidity, heat or at high altitude)

Suitable for

Very experienced long distance ultra runners (min 3 years’ experience) or are doing regular long distance running (>50 miles) with elevation and conditions shown (where possible). Admission to these races is often subject to receipt of a recent medical examination certificate. Purchase of specialist kit is often recommended for these races.



Increase of up to 2000 metres with some challenging climatic conditions (e.g. ice, snow, humidity or heat)

Suitable for

Experienced runners who have completed at least 4 ultras in last 12 months, or are doing regular long distance running (>50 miles) with elevation and conditions shown (where possible). Admission to these races may be subject to receipt of a recent medical examination certificate. Check with the race organiser regarding entry requirements.



Increase of up to 1500 metres

Suitable for

Runners who have completed several ultra distances or similar events, or are doing long distance running regularly, with elevation shown.



Increase of up to 1000 metres

Suitable for

Runners who have completed at least one ultra in last 6 months or are doing long distance running (>26 miles) regularly, with elevation shown.



Very little change < 500 metres

Suitable for

First ultra event. Runners completing a marathon or doing regular long distance running (>26 miles) in the last 6 months.