Training for a Longer Day
Trail Notes | Coaching Principles
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. In our coaching experience, the return from a single continuous effort flattens out past roughly 2.5 to 3 hours, while the recovery cost of that effort (muscle damage, connective tissue load, immune stress) keeps climbing. In a 50km build, push a long run out to 5 or 6 hours and you are paying a steep bill for a small return.
The principle we coach to in 50km programs is simple: cap the single longest run at around 75% of race distance and treat it as a rehearsal, not an engine. Training days of 5 and 6 hours are, for most of us preparing for a 50km, high cost, low reward, and hard on the mind. A first 100km is different. Its peak long sessions sit in the 5 to 6 hour range because the race itself runs 13 hours or more. Our Trail Note "Your First 100km" covers that build.
So in a 50km build we hold the ceiling on the long run at roughly 4 to 4.5 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 most of the tired-legs benefit at a fraction of the injury cost.
Three
Hold the long-run ceiling
4 to 4.5 hours is the cap in a 50km build, 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 4 to 4.5 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 far less impact. 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 one of the most common reasons 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 thinking
Why we coach it this way
The long run has a ceiling. This is Her Trails coaching practice, drawn from how ultra coaches commonly structure a build, rather than a figure from a single study. In a 50km build we cap the longest run 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. In our experience the benefit of a single effort flattens past about 2.5 to 3 hours while the recovery cost keeps rising. Longer races, such as a first 100km, carry longer peak sessions because the demands of the day are different.
Two moderate days beat one enormous one. Splitting the load across a weekend rather than a single mega-run is a widely used coaching approach. It gives a similar cumulative stimulus at a lower injury cost, and it rehearses the state you actually race in: already tired.
Low-cost time on feet is real training. Hiking and walking let you accumulate hours on your feet with far less impact than running. That is the basis for the long hike rehearsal: hours on your feet, minimal damage. Again, this is coaching practice rather than a finding from a specific trial.
Recovery is a limited resource. Most of the athletes we coach are fitting training around work, family and, for many, the menopause transition. A longer day on feet adds recovery cost on top of an already full life, which is a practical reason to cut the second long day rather than stack it. It also matters because low energy availability is linked to bone stress injury and wider health effects in athletes (IOC consensus statement on Relative Energy Deficiency in Sport, Mountjoy et al. 2023; international Delphi consensus on bone stress injuries, British Journal of Sports Medicine 2024). See our Trail Note on the causes of bone stress injuries.
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 low energy availability (IOC REDs consensus, Mountjoy et al. 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.
