Training for a Longer Day
Coaching Principles
Training for a Longer Day
How to adapt Weeks 10 to 20 when your race day will be longer than the program assumes.
Every training program carries an assumption about how long your race day will take. It is baked into the long runs, the back-to-back weekends and the peak week, usually calibrated to a median finish time. If your day out there is going to be considerably longer than that assumption, the program still works, but it needs reshaping.
The instinct is to add. Longer race, longer long runs. That instinct is wrong, and following it is one of the most reliable ways to arrive at the start line tired, undercooked or injured. What you actually need is more specific time on feet and less fatigue. Those are not the same thing, and this is how you get both.
The principle
Reshape the week, do not extend it
A longer race does not license a longer long run. The evidence is consistent: adaptation from a single continuous effort flattens out past roughly two and a half to three hours, while the recovery cost of that effort (muscle damage, connective tissue load, immune suppression) keeps climbing. Push a long run out to five or six hours and you are paying a steep bill for a small return.
The principle we coach to is simple: cap the single longest run at around 75 per cent of race distance and treat it as a rehearsal, not an engine. Five and six hour training days are, for most of us, death marches: high cost, low reward, and mentally corrosive. So we hold the ceiling on the long run at roughly four to four and a half hours, and we change the shape of everything around it.
A longer race does not license a longer long run. Hold the ceiling, and change the shape of the week instead.
What to change
The five adjustments
One
Swap the second hard run for a hike-jog
Most programs carry two quality sessions. Keep one. Replace the other with 60 to 90 minutes of easy hike-jog on hilly trail: power-hike every climb with intent, jog the flats, stay conversational. This is the highest-value swap in the whole plan.
Two
Cut the second long day
On back-to-back weekends, keep the long Saturday but cut Sunday to a 60 to 75 minute walk-jog. You get almost all of the tired-legs benefit at a fraction of the injury cost.
Three
Hold the long-run ceiling
Four to four and a half hours is the cap, and it stays the cap. Do not stretch it because your race is longer. This is the change people most want to make, and the one that hurts them most.
Four
Add a full rest day
Convert a weekday base run to complete rest. You are accumulating more time on feet than the program assumes, so you need more recovery, not less.
Five
Scale up the hike rehearsal
In your absorption week (around Week 15), extend the hike rehearsal to four or four and a half hours in full race kit with race fuel, at a very easy effort. This is the closest safe approximation of a long day, and it is the session that changes the most.
Notice what these five have in common. Every one of them trades intensity for specific time on feet. The hike-jog builds climbing endurance and your run-walk rhythm at a fraction of the recovery cost of a threshold session. The long hike buys hours on your feet with almost no impact damage. You end up with more of the adaptation your day actually demands, and less of the fatigue.
The back half
Weeks 10 to 20 at a glance
What actually decides the day
The skills, not the mileage
Over a long day you will walk a meaningful portion of the course. So walking is a skill to train, not a fallback to apologise for. Power-hike every climb with intent, jog the flats, and practise the exact rhythm you will hold on race day. Run your long runs at race-day effort rather than your everyday training rhythm. That acceptance is trainable, and it is what holds you together in the final third.
Fuelling is where long days are won and lost. A longer day gives you more eating windows, which works in your favour, so aim for steady, constant intake rather than occasional big hits, and rehearse it on every long run at race effort. Under-fuelling is the single most common reason a long day unravels, and it rarely announces itself as hunger. It shows up as flatness, low mood, or a decision to stop that feels rational at the time.
Then the practical layer: rehearse your full race kit from Week 10 so nothing is new, learn to use poles well before race week if your event permits them, and if your projected finish runs past sunset, spend real time on trail with a headlamp so darkness is familiar rather than frightening.
Walking is a skill to train, not a fallback to apologise for.
The evidence
Why we coach it this way
The long run has a ceiling. The single longest run is best capped at roughly 75 per cent of race distance, because the ability to finish is accumulated over months of consistency, not bought in one hero run. Adaptation flattens past about two and a half to three hours while recovery cost keeps rising.
Two moderate days beat one enormous one. Splitting the load across a weekend rather than a single mega-run produces a similar cumulative stimulus at meaningfully lower injury risk. It also rehearses the state you actually race in: already tired.
Low-cost time on feet is real training. Vitiello and colleagues (2021, Frontiers in Physiology) studied a 100km walking march and found trained bodies tolerate long, low-intensity time on feet with predictable, manageable physiological stress. That is the basis for the long hike rehearsal: hours on your feet, minimal damage.
The recovery bill lands harder on women. Female athletes recover neuromuscularly more slowly (Davies 2018) and carry roughly three times the bone-stress-injury risk of men, tightly linked to low energy availability and menstrual disturbance (Heikura 2021). That is a direct argument for cutting the second long day rather than stacking it.
Long days are where fuelling collapses. On a 10-plus hour effort you can burn several thousand calories and cannot refuel in real time, which is a direct route into relative energy deficiency (IOC REDs consensus, Mountjoy 2023). Fuelling is not a detail here, it is the plan.
Keep going
Further reading
The long run
Why We Choose Consistency Over Epic Long Runs
The case against the hero run, in full.
Back-to-backs
Shaping Your Ultra Weekends at Every Age
How to build the weekend that actually serves you.
Power hiking
How to Handle Steep Climbs Without Burning Out
Making the climb a strength, not a cost.
Poles
Running Poles: When and How to Use Them
Worth their weight on a long day, if you train with them.
Fuelling
How to Fuel for Long Runs Without Gut Issues
Train the gut before race day asks you to.
Energy availability
REDs and Under-Fuelling
The risk that grows with the length of your day.
Absorption
Why the Deload Week Is Where Progress Happens
Weeks 12, 15 and 17 are doing more than you think.
The short version
Do not add volume, change the shape. Swap the second hard run for a hike-jog, cut the second long day of the back-to-back, hold the long-run ceiling, add a full rest day, and make the hike rehearsal big.
Train the skills that decide a long day. Walking, pacing, fuelling, kit, and darkness if it applies. These matter more than another hour of running.
Your day is a duration, not a verdict. A longer time on feet is a different race to prepare for, not a lesser one. Prepare for the day you are actually going to have.
