If I Were Training To Pass UKSF Selection: A Coach's Plan

Let me deal with the elephant in the room first. I have never passed UKSF Selection. I have never stood on the start line of the Fan Dance with a bergen and a rubber duck. I'm a civilian. I'm forty. My knees make sweet sweet music going up the stairs and I haven’t slept properly for years thanks to my daughter.

So why write this at all?

Because the physical preparation for Aptitude phase isn't a secret held only by the men who've passed it. It's a physiology problem, a psychology problem, and a logistics problem, and I've spent my career working on exactly those three things. My background is in strength and conditioning, sport and exercise science, sports performance psychology, and physical therapy. I've coached tactical athletes and selection candidates from around the world, watched some of them succeed, and watched others come home early for reasons that were entirely predictable months in advance.

What follows isn't war stories. It's the plan I'd build if I were the athlete, using what the evidence says and what I've learned across 22 years of coaching. I'm going to write it in the first person because that's the honest (and fun) way to frame it. This is what I would do. Take it as a coaching model, not gospel from a man with a specific-coloured beret in a drawer.

One more bit of context because it’ll matter for the numbers I'll use later. If I were actually doing this, I wouldn't be doing it at forty (not that you can’t do it). I'd be doing it in my late twenties/early thirties, which is where most candidates sit age-wise. I'm going to write the standards as if I were that younger version of me. The forty-year-old ultra-caffeinated version just gets to do the typing.

Passing in spite of, not because of

Before any of the training, a warning about how to read the advice you'll get from people who've been through it.

Selection is survivorship bias in its purest form. The men who pass are, by definition, the ones still standing, and they'll tell you what they did to get there. The trouble is, they can't tell you what they'd have got away with regardless. Some people pass in spite of their preparation, not because of it. Just because one dude got through the hills phase by doing no training, eating Pringles and drinking milk doesn't make that a decent training and nutrition strategy. It makes him lucky, or robust, or both.

That's the danger with course lore - you hear the plan that worked for the person telling the story, stripped of all the context that made it work for them, but might end your run at it very early. Genetics, training history, injury luck, the weather on the day. So I'd take anecdotes as interesting rather than instructive, and build my personal plan from what actually predicts performance across many people, not what one survivor swears by. That's the whole reason I lean on evidence sprinkled with a lot of experience in the application of evidence, as a coach. Not because it's clever, but because it's the only thing that travels between one body and the next.

The problem I'd actually be facing

Here's my honest starting position. I walk around at about 110 kg. My early sporting background is rugby, track and field (all events in the power realm - sprints and throws rather than anything long), various martial arts, plus strongman, bodybuilding, and CrossFit when I felt like being humbled. My best ‘gym lifts’ would put me just shy of the Elite category for powerlifting. I am strong, but to paraphrase Gimli, I'm wasted on cross-country; I’m a natural sprinter…Very dangerous over short distances.

On paper, I'm built for the wrong job.

However, more recently, I've deliberately turned myself into something else: strong and athletic still, but also able to run ultramarathons unassisted, mostly for fun and as a way of testing different training approaches on myself. So I know from the inside what it takes to drag a big, heavy frame with a strength background towards long-endurance work. It can be done. It just has to be done properly and patiently.

The hills phase (Aptitude) is a very long, very high endurance task performed under load on brutal terrain. The Fan Dance is roughly 24 km over Pen y Fan carrying a 20 to 25 kg bergen plus a rifle, and the standard sits around 4:10. Test Week stacks multiple timed marches of 23 to 28 km on consecutive days, then finishes with Endurance: 64 km, over 40 miles, across the Brecon Beacons, inside 20 hours, with a bergen around 25 kg before you've added water, food and weapon. Roughly nine in ten candidates don't make it through the wider process.

Nothing about that instantly rewards a 200 kg squat on its own. It rewards a big, efficient aerobic engine attached to a frame that can carry itself all day and is strong enough not to break from carrying various loads day in day out. To be a tractor, not a Ferrari - something that can just keep on going.

So the strength-biased athlete has a specific job. Keep the strength that protects their tissues, moves the load and makes efforts less…effortful. Build an aerobic system to a standard it currently doesn't reach. And lose the dead weight, without losing the useful kind.

Why bodyweight is the first area I’d address

This is the part strength athletes tend to resist, so best to lean into it first.

At 110kg, every step on the hill costs me more than it would cost the 85kg man next to me. The load carriage research is consistent here. The metabolic cost per kilometre rises with total mass (yours plus the bergen's and anything else you have to carry), and running economy suffers for it (Knapik and colleagues have written on this for years). The hill doesn't care whether the weight is on your back or around your middle. It's all just load.

But there's an important nuance, and it's why I wouldn't crash down too far. Larger, stronger athletes can handle heavier absolute loads by virtue of more bone and muscle, and fat-free mass is itself a predictor of load carriage performance. One study on cadets found each additional kilogram of fat-free mass meaningfully raised the odds of completing a foot march. Carrying a little extra useful mass, and a little extra stored energy for a multi-day event, is not a bad thing. Bodyweight also carries over into your ability to handle external load on the body in the first place.

So the target isn't "light." It's "lean enough, strong, and no heavier than it needs to be." For me, that means stripping from around 110 kg to somewhere in the 95 to 100 kg range. I already sit fairly lean for my size, and that range is about the lowest I'd want to go without shedding strength or getting too lean to carry load and store energy well.

I'd want to be at that weight as early as possible, and (importantly) as far out from the course as I could manage.

Dropping 10 to 15 kg is not a problem you should be solving in the final block. It's a body I need to live in and train hard in for months before I turn up, so that my tendons, my running economy and my thermoregulation have all adapted to the lighter frame. There's also a bit of a trap here too: trying to improve your tabbing while sitting in a calorie deficit is asking for an injury. You're adding a novel, high-impact loading stress at the exact moment your recovery is compromised - you’re going to get a bone fracture. Lose the weight first. Then build the tabbing on a fed, recovered body.

On the personal side, I'm fortunate that this part comes easily to me. I’ve spent some of my career at arguably one of the best body composition facilities in the world, where being lean year-round was part of the job, and I had to drop a fair amount of body fat just to get in the door. Stripping 10 to 15 kg relatively quickly is familiar territory for me. For plenty of people, it isn't, and they'll need to give it a longer, gentler runway. Either way, the principle still stands: do it early.

Table 1. The bodyweight plan I'd commit to first, because it changes everything downstream.

The 12-month shape of it

I'd give myself a year and split it into four blocks of roughly twelve weeks. The logic is simple. Build the engine and shed the weight while the training is least specific, then get progressively more specific to the hill and the Bergen as the course approaches. The strength work never disappears. It just changes its intention, from building to maintaining.

Table 2. A twelve-month structure. The weight comes off early on purpose.

Block 1: build the engine, and change the kind of strength I own

My biggest physiological gap is aerobic. Track sprints, throws and heavy lifting don't build the low-intensity, high-mitochondrial system that lets you march at 40 to 45 per cent of your maximum for hours on end and day after day. So the first block is unapologetically aerobic.

The bulk of it would be Zone 2. Easy, conversational, nose-breathing steady-state work, on foot but with a fair amount of low-impact modalities early to spare the joints while I'm still heavy. This is the least glamorous training you can do and the most important thing I'd be doing. Zone 2 develops the aerobic base with very little interference to strength, because it works at an intensity the strength pathway largely ignores. The classic polarised model is roughly 80 per cent easy work and 20 per cent hard and I’d stick daily close to those ratios.

A common mistake is treating every run like a test. You go out too hard, spend the session in the ‘grey zone’ that's too fast to build the base and too slow to be genuine high-intensity work, and end up tired without getting fitter. Higher discipline in Block 1 means going slower than your ego wants.

On the interference question, since a strength athlete will worry about it: the interference effect between endurance and strength is heavily overstated in gym folklore. It was first documented by Hickson in 1980, and decades of work since show it's easily manageable with a few sensible rules. Separate your hard aerobic and hard strength sessions by several hours where you can. Put strength first on any double training days. Use lower-eccentric aerobic modalities like the bike or rower when you want the aerobic stimulus without trashing your legs. Do that, and you keep most of your strength while building the engine. However, unless you're spending an obscene and probably unnecessary amount of time doing conditioning work, you're not going to lose a lot of strength, even if you only do one meaningful session a week.

There's a second job in Block 1 that's specific to someone like me. A lot of my strength is static, slow, gym strength, the kind you express against a heavy bar. Selection asks for more elastic, athletic strength you can express step after step over hours on uneven ground. So I'd spend this block converting some of that raw force back into springiness: plyometrics, pogos, bounding, short hill sprints, low-level jumping and landing work. Built with patience and managed expectations, this improves tendon stiffness and running economy and makes the frame more efficient under load. The goal is a body that recycles elastic energy well, not one that muscles every stride.

Strength itself stays central in Block 1, because I'm not trying to become a runner who used to lift. I'm trying to stay a strong, athletic person who can now go all day. Heavy compounds and unilateral work, squat, deadlift, press, pull, twice or three times a week, alongside the plyometric and sprint work, with the emphasis on keeping the tissue robust and turning static strength into athletic output rather than chasing new maxes I don't need.

Block 2: volume, and hitting the weight

By the second block, the aerobic base is significantly better and I should be moving well enough to build higher volume without having to baby it too much. This is where the weekly running and tabbing distance starts to increase, and where I'd want to be arriving at my target bodyweight.

Load carriage enters more predominantly here, and how you introduce it matters far more than the weight on the first day. I've written about this at length in Improving Tabbing Performance, and the single message is patience. If you've never tabbed, or haven't tabbed in years, the adaptation demand is enormous and the tissue recovery/adaptation timeline is slow. Tendons and bone adapt over months, not weeks. The engine adapts faster than the chassis, which is exactly why people who rush their loaded carrying pick up shin splints, stress reactions and Achilles trouble right when their fitness is finally coming good. I'd add load, speed and/or distance conservatively, one variable at a time, never more than one in the same week.

This is also the second reason the weight comes off first. If I'm still in a deficit when I start piling on tabbing volume, I'm layering a novel high-impact stress onto a body that can't recover from it. That's not toughness. That's a stress fracture with a countdown timer.

Table 3. An example of a load carriage build across Block 2. Add one variable at a time.

Another note that comes up a lot: downhill work should be thought of as a skill, and it's the one that wrecks people the most if they’re not used to it. The Beacons go down as much as they go up, and the eccentric braking of descending under load is what shreds quads and knees. Coming from a strength and power background, I'd actually have an advantage in eccentric tolerance if I trained it deliberately, so I'd practise controlled downhill walking and running early, building the tissue's capacity to absorb force rather than discovering the deficit on the hill.

Block 3: make it specific

Now the training starts to look like the course. Longer tabs at course loads over the kind of terrain I'll face, navigation layered on top, and pace work so I understand what the standard feels like in my legs rather than as a number on a plan.

The rough yardstick people talk about for aptitude is 4 km/h as the crow flies. The catch is that nothing in the Brecon Beacons is flat, so that straight-line pace demands a much higher working effort over the real ground, up and down, boggy and broken, clear skies or hideous clag. That's the argument for specificity in its purest form. You cannot fake this on a treadmill or a canal footpath. You have to get out into actual hills, on actual terrain, under actual load, and learn what holding that pace costs you.

This is also where I'd stress-test the psychology and nutritional aspect of things too, because in Block 3 the sessions become long enough to break you a little and teach you how you respond and see where your energy deficits might lurk.

Strength here is pure maintenance. Two sessions a week, submaximal, enough to hold the numbers and keep the tissue resilient, not enough to leave me sore for the tabs that now matter more. This is the minimal effective dose in practice. I'm not looking at adding anything here; I’m just holding onto what I’ve built already.

Block 4: come in rested, not rusted

The final block consolidates everything and then eases off. The temptation before a course is to keep piling it on out of anxiety and panic, which is how you arrive flat and beaten up. But the opposite mistake matters too. Strip the training back too far and you turn up rested but rusty, having lost the sharpness you spent a year building.

So the aim is rested, not rusted. I'd pull volume back enough that fatigue fades away and doesn’t mask my fitness and the adaptation surfaces, while keeping enough quality work that my mind and body stay switched on. I'd rather walk to the start line a fraction underdone than over-tapered and stale.

A qualifier on this, because deloads get overthought a bit. The classic, aggressive taper is really a tool for single-event, single-day athletes peaking for one moment: a sprinter, a powerlifter, a marathoner on race day. Aptitude is a multi-day, multi-event grind. For that kind of demand you don't need to major in the minors with an elaborate taper. You need durable, repeatable readiness, not a razor-sharp one-off peak. Ease off sensibly and don't overcomplicate it.

I'd also use this block to keep rehearsing the unglamorous daily operational details that quietly decide some people’s outcomes. Foot care and taping. Fuelling and hydration on the move. Kit packing so the bergen sits right. Recovery methods in the down times. These sound trivial until a hotspot becomes a blister at kilometre 30 and your day suddenly becomes a battle of will and is over for reasons that have nothing to do with fitness.

The benchmarks I'd want to hit

A firm caveat before the numbers, and I mean firm. None of the gym figures below are official Selection tests. They are coach-administered benchmarks I would use to judge whether I personally was ready, drawn from what I've seen in the load carriage literature and from my own coaching experience. They are for me, in my situation, at my starting point. Please don't frame yourself against them, treat them as targets, or assume a DS will ever measure any of this or give a shit about them. The formal, tested standards on Selection are things like the swim assessment and the timed marches, and nothing here replaces those.

I'd frame my personal gates Red, Amber, Green. Red means not ready and at real risk. Amber means capable but with a clear weakness to work on as an opportunity to get physically better. Green means I'd be content to stand on the start line.

Table 4. My personal Red / Amber / Green readiness gates. These are my own coaching benchmarks, not official Selection tests, and not standards anyone else should hold themselves to.

The swim line matters more for the more strength-based athlete than expected. The Briefing Course includes a swim assessment: high entry, treading water, a timed swim, and an underwater retrieval. A heavy, muscular frame that’s not confident or competent in the water and sinks is a liability, which is another quiet argument for arriving lean and happy in the water…rather than merely big.

Heat, and why I'd pick a winter course

In July 2013, three men died as a result of a Selection march in the Beacons after suffering exertional heat illness on one of the hottest days of the year. The subsequent inquiries found a poor understanding of heat-illness risk at multiple levels. It's one of the reasons, in my opinion, that talking about heat deserves a section rather than just a short footnote.

Heat is a trainable variable and can be a massive unexpected ass kicking if not familiar with it. If I had to prepare for a summer course, I'd build seriously robust heat acclimatisation sessions into my plan in the weeks beforehand, train in the conditions I'd face rather than avoiding them, treat hydration and electrolytes as something programmed to the minute and that will save me rather than an afterthought, and learn the difference between pushing through discomfort and ignoring the early signs of a body that's overheating.

But if I had the choice, I'd pick a winter course over a summer one, and that's a personal call based on knowing my own physiology. A bigger, more muscular athlete generates and retains more heat and has a harder time shedding it. I'll suffer more in extreme heat than I will in extreme cold, where I can add layers, keep moving, and use my mass to my advantage. Cold has its own dangers and I wouldn't take them lightly, but if I'm playing to my build, the winter hills suit me better than a heatwave on Pen y Fan…plus I like the rain… it hides my tears.

Nutrition and supplements

I've talked about stripping bodyweight already, but that's a Block 1 and 2 focus. The bigger nutritional theme across the whole year is energy availability. Under-fuel a body that's running, lifting and tabbing 15-20 hours a week and everything downstream starts to break down: recovery slows, tissue repair stalls, hormones dip, mood tanks, and injury risk climbs. That initial fat-loss deficit is a tool for the early blocks, not a way of life after hitting the ideal ‘fighting weight’. By the time I'm doing serious running volume with load, I'm eating to support that adaptation demand, not fighting it.

For an event like this, carbohydrate is the main currency of choice for energy. Aptitude is long-duration, glycogen-dependent work, so this is not the place to be a low-carb hero because you read a book about ketones on a beach or some knobhead is shouting about it with their top off in a supermarket. I'd keep glycogen topped up around the hard sessions and practise eating on the move, because the gut is trainable and if your gut has never seen a gel four hours into a training session…will absolutely let you know about it in very unconstructive ways. Somewhere around 60 to 90 g of carbohydrate an hour on the very long stuff, tested to death in training and never trialled for the first time on the day.

Protein has a quieter role of protecting the muscle I'm trying to keep while leaning down and repairing the tissue I'm hammering in training. Roughly 1.6 to 2.2 g per kg of bodyweight per day - the upper end matters more when you're in a deficit. Hydration and electrolytes I've touched on under heat, but the short version is that sodium is not the enemy here so salt your damn food, and your hydration strategy is another skill to rehearse, not a bottle you grab at the start line and hope for the best with - I’d personally head to Precision Fuel and Hydration in Bournemouth to work with them on the best strategy for hydrating (and then guess what…I’d test that a lot too).

Now onto supplements, and I'll be blunt because…well I always am and the supplement industry sucks. Food, sleep and good, planned training do about 95 per cent of the work. Supplements can be the last few per cent, and they're only worth touching once the boring basics are genuinely nailed. Buying tubs to paper over bad sleep, shit food choices and no plan is just expensive urine.

The short list with actual evidence behind it is, well it’s short:

Creatine monohydrate, cheap, absurdly well-studied, helps build and retain strength and power and may take the edge off fatigue (dose dependant).

Caffeine, for performance, pain mitigation and alertness.

Whey or a protein source for convenience.

Vitamin D if you're deficient, which most of the country is.

Multi vitamins, fish oils and magnesium would round out my list.

That's most of it. Fat burners, exotic pre-workouts and whatever 'adaptogen' is trending this week are mostly marketing and lies. Keep your money.

One serious note that matters more for this audience. Anything you put in your body is your responsibility, and the supplement industry is poorly regulated and riddled with contamination. If you're serving, or intend to be, stick to products that are batch-tested through a scheme like Informed Sport, and check anything against the current banned list. Failing a drugs test because of a dodgy pre-workout you bought off an advert is a spectacularly stupid way to end a career before it's even started.

The psychology

This is the area where my background helps a load: sport and exercise science, sports performance psychology, and a range of psychology and therapy-based courses I've taken over the years.

The research on who passes these courses is reasonably clear, and it's not simply the fittest or the toughest. Success tracks with a cluster of psychological factors: conscientiousness, resilience, grit, and, sitting underneath a lot of it, self-efficacy, the genuine belief that you can do the thing you’re setting out to do. Self-efficacy shows up repeatedly as a mediator between resilience and actual course performance. Put plainly, believing you can cope is part of what lets you cope.

That belief isn't something you conjure with motivational noise the night before. It's built, brick by brick, from evidence you give yourself in training. Every long tab you finish when you wanted to stop is a deposit in that account. This is why I'd design the plan to include sessions that are ‘hard hard’ (can’t or won’t type sessions), make me second guess if I even know what the hell I’m talking about, not to grind myself into the ground for its own sake, but to accumulate honest proof that I can keep going when it's grim.

Underpinning all of it is a growth mindset: the working assumption that these capacities are built, not fixed, and that today's ceiling is just where the work has reached so far. If you believe your limits are set in stone or inherited, you stop training the moment it gets uncomfortable, because discomfort feels like the wall. If you believe they move and can be trained, discomfort is just the next bit of road.

On self-talk, I'd use both kinds deliberately. Positive, instructional self-talk is the reliable tool for most people, keeping you task-focused and steady. Negative self-talk gets a bad name, and for good reason if it spirals, but a sharper, more challenging internal voice does genuinely fire some people up and drive them on, myself included. It's individual. The point isn't which one is correct. It's knowing which one works for you under fatigue, and having practised it, because a strategy you've never used at kilometre 50 isn't a strategy, it's a hope.

I'd also practise negative visualisation: deliberately rehearsing what could go wrong, the blister, the bad weather, the navigation error, the moment I want to quit, so that when it arrives it's familiar rather than catastrophic. Done well, it isn't pessimism. It's preparation, and it takes the sting out of adversity by removing its surprise.

Where Stoicism comes in, for me

I‘ve always enjoyed and used Stoicism (good thing really considering the company name…), but it's a personal preference, not a prescription. The measure of any philosophy is whether it works for you. What works for me doesn't have to work for anyone else, and if it doesn't fit, discard it.

For me it's fairly pared back. Meditation works, and I lean on breathing strategies as a form of meditation and mindfulness, a way of steadying things under stress. Outside of that I don't use much, and I'm wary of people who turn a simple practice into a personality type and put it in their bio.

The other half is practical rather than contemplative. I systematise the things I have to do day in, day out, so they become habits I don't have to decide on. And I manage my surroundings deliberately: work, relationships, the house, finances, life in general, kept as clean and ordered as I can keep them. The point is mental bandwidth. Every bit of mental energy spent on avoidable chaos is energy not available for the goal/training programme. Order the small things so the big thing has room to take up the space it needs.

This is also where another of my strengths lies. Because I've deliberately put myself through a wide range of physical and mental challenges, from strength and power sports to unassisted ultramarathons, I've built a fairly deep well of self-knowledge about how I respond when things get hard. It's data on myself for me to call on, and it's the most useful thing I'd bring to a start line.

The people around you, and the fact that nothing is ever perfect

There's a part of this that has nothing to do with your legs or engine and everything to do with the people you live with.

Selection preparation is a part-time job layered on top of a full-time one, and often on top of a family. Ten to fifteen hours of training a week, much of it long, much of it at unsociable times, over a full year. That doesn't happen in a vacuum. It happens in a house with a partner, maybe children, maybe a job that doesn't care about your training schedule.

Social support is one of the protective factors that underpins resilience in the research, and I mean that practically. The candidate whose partner understands why he's out on the hill every Sunday morning because they’ve had a meaningful conversation about it to align expectations has a real advantage over the one managing resentment at home alongside the training load. So I'd treat the conversation with the people I live with as part of the preparation, not separate from it. I'd be honest about what the year demands, involve them in the why, and protect those relationships deliberately rather than assume they'll survive on goodwill and address any disagreement instantly and candidly rather than letting it fester.

But here's the thing that has to underpin the whole social and logistical side: nothing is ever perfect. The ‘plan will not survive contact’ with real life. Someone will get ill. Work will throw a curveball. A session will get binned because a kid didn't sleep. The question isn't whether things go wrong, it's what you do when they do. So I'd build the plan expecting imperfection, with a clear idea of how I respond when it hits the fan: what I protect first, what I let slide, how I get back on track without spiralling about the day I missed. 

This is exactly where Stoicism and knowing yourself pay dividends. You can't control the disruption. You can control your response to it, and a candidate who's rehearsed that stays on the road while a more fragile one falls off it at the first setback.

The culture around Selection is worth managing here too, because it ties straight back to survivorship bias. It's thick with lore, some useful, plenty of it nonsense dressed up as excuses or tradition about how much you must carry and how broken you must get. Junk volume for its own sake, sold as toughness, is how people arrive on the start line already injured. I'd take the terrain seriously and the folklore very lightly.

Sleep and recovery sit here too, because they're social as much as physiological. Protecting eight hours a night when you have a young family and a job is a negotiation with the people around you, not simply a discipline you impose on yourself. But it's non-negotiable. You don't adapt to the training load that you don't recover from. You just accumulate fatigue and call it hard work.

What I'd hold onto if I forgot everything else

If a version of me were to stand at the bottom of Pen y Fan with a year of this behind him, the plan would come down to a handful of principles.

• Get lean early, keep useful mass, and train as the lighter athlete for as long as possible.

• Build the aerobic engine patiently, and don't confuse tired with fit.

• Turn static gym strength into elastic, athletic, multidirectional strength.

• Add load slowly enough that the chassis keeps pace with the engine, and never tab hard in a deficit.

• Get onto real hills for the specific work, because straight-line pace hides the demand.

• Come in rested, not rusted.

• Bank real evidence that you can cope with physical and mental stress, and know which mental tools work for you.

• Plan for imperfection, because nothing ever goes to plan.

• Bring the people around me with me on the journey as much as I could.

I don't know what it's like to go on aptitude. I've never been, and I won't pretend otherwise. But I've been a coach for 22 years, and I've prepared myself across a wide spread of physical challenges, from strength and power sports to unassisted ultramarathons. I know, from the inside and from the evidence, what an intelligent year of preparation looks like, because building exactly that is what I do for a living.

Frequently asked questions

What is the Aptitude (Hills) phase of UKSF Selection?

The Aptitude phase, commonly called the Hills phase, is the endurance and navigation stage in the Brecon Beacons and the hardest physical test in the process. It runs through timed loaded marches, including the Fan Dance and Test Week, and finishes with a 64 km Endurance march. It's where physical preparation most directly decides who continues. The later stages of Selection test different qualities and sit outside the scope of this article.

How fit do you need to be for the aptitude phase?

Ummm…pretty fit. Fit enough to march 24 km over mountainous terrain carrying a 20 to 25 kg bergen and rifle at around a 4 km/h straight-line pace, then repeat consecutive marches across Test Week and finish a 64 km Endurance march inside 20 hours. In practice that means a large, efficient aerobic base, robust load-bearing tissue, and enough retained strength to move the load without breaking down that much from march to march. Raw gym strength alone is nowhere near sufficient but neither is just being a good runner.

Should I lose weight before the hills phase if I'm a heavier, fatter or more muscular athlete?

Usually some, and the earlier the better, but not to extremes. Total mass drives the metabolic cost of every kilometre, so genuine dead weight is worth shedding. The nuance is that fat-free mass predicts load carriage performance and some stored energy helps across a multi-day event, so keep useful mass. Get to a sensible target months out and train as the lighter athlete, rather than crash-dieting in the final block or tabbing hard while in a deficit.

How should I fuel my training, and do I need supplements?

Fuel the work. Once the early fat-loss phase is done, eat enough to support big tabbing volume adaptations, keep carbohydrate high around long sessions, and practise eating and drinking on the move so your gut is trained for it. Supplements are the last few per cent: creatine, caffeine, protein, vitamin D, fish oils, magnesium and multi vitamins cover most of the useful ground. If you're serving, only use informed sport tested products and check the banned list, because a contaminated supplement is a stupid way to fail a drugs test.

How long does it take to prepare for the aptitude phase?

For someone already serving and reasonably fit, a structured 6-12 months is a sensible runway, split into base, build, specific and peak phases. Someone rebuilding a weak aerobic base, new to tabbing, or shedding significant weight may want eighteen months to do it without rushing the tissue adaptations, which take months rather than weeks.

Can strength training hurt my endurance for the hills phase?

Not if it's programmed sensibly. The interference effect between strength and endurance is overstated. Separate hard sessions by several hours, run strength second on doubles days, use low-eccentric aerobic modalities when you want the engine work without trashing your legs, and shift strength to maintenance as the course nears. Retained strength, ideally converted into elastic, athletic output, protects your tissues and helps you carry load.

What actually predicts who passes the aptitude phase?

Physically, aerobic capacity and power, strength, muscular endurance and lean mass all track with load carriage performance. Psychologically, the research points to conscientiousness, resilience, grit and, underpinning much of it, self-efficacy, the earned belief that you can cope, alongside adaptive coping and genuine social support. Be wary of survivorship bias, though: what one person got away with isn't a plan, it's their luck plus their history.

Is running or tabbing more important for hills-phase prep?

Both, in the right order. Build the aerobic engine first through mostly easy running and low-impact work, then layer loaded tabbing on top progressively, adding distance and weight one variable at a time. Tabbing is the specific skill, but it sits on top of an aerobic base and enough strength training to build robust tissues that plain running and patient loading build first.