The honest difference: past tense vs future tense
Open whatever you currently use to "train." A wearable app, a spreadsheet, a generic fitness tool. Look at what it tells you. Does it show you what you did yesterday, last week, last month? That is a log. Does it tell you what to do today, this week, next? If the answer is no, you do not have a training plan; you have a record.
A log is backward-facing. It catalogues your sessions, plots your trends, lets you compare this Sunday's run to last Sunday's. It is genuinely useful. A plan is forward-facing. It uses what you did to decide what you do next. Both tools belong in a real training stack. The mistake, and it is the most common one in amateur mountain training, is calling the first one the second.
A log is a mirror. A plan is a compass. You need both, and they are not the same instrument.
A log doesn't know your objective
A log accepts any workout. Five hours on flat road, five hours of vertical, five hours in a gym - same colour green dot. To the log, training is whatever you record. That works for general fitness. It does not work for a mountain.
Mountains have a demand profile. Mt Rainier wants weighted carry capacity and crevasse-rated rope-team endurance. Mont Blanc wants a 12-hour summit day with 1800m (5,900 ft) of descent on tired legs. Aconcagua wants altitude tolerance across a 17-day expedition. A 5km easy run is data. "Zone 2 capillary density session, 90 minutes, 600m (2,000 ft) gain, descend the same drop under control" is a prescription tied to a peak. Without that prescription, the data goes in but nothing comes out aimed at where you are going. See our peak-by-peak training pages for what objective-aware actually looks like.
A log doesn't change next week
This is the adaptation gap. Your week's data sits in the log. Next week's program looks the same. If you had a heavy work week and missed two sessions, the log will show two missing entries; the program for next week will still demand its scheduled progression. If you smashed every session and recovered fine, the log will show green; the program will still hold back the load it would have held back anyway.
A real plan reads the data and rebuilds. The Banister training-impulse model (Banister et al., 1975) describes how every session adds both fitness and fatigue on different decay curves; the next week's prescription depends on the balance. If fatigue spiked, the plan deloads. If cardiac drift narrowed at the same effort, the plan adds load. The test: when your week goes off-plan, does anything change for the following week without you intervening manually? If you have to email someone or rebuild the program yourself, your stack is open-loop. See the science behind TTM for how this loop closes.
A log treats every session as equal
In a log, a Tuesday recovery jog and a Sunday long climb are two equal entries. Both colour the calendar green. A plan knows the Sunday is the keystone session of the week and the Tuesday exists to protect it. Drop the keystone and the whole week's purpose collapses. Drop the Tuesday and you might be fine.
This matters more in mountain training than in most other endurance sports because the specific stimuli, eccentric descent loading, summit-day rehearsal, weighted carries, hypoxic tolerance, need to be programmed distinctly. Averaging them under "hours trained this week" hides the gaps. A plan never averages keystone sessions into noise. A log has no way not to.
A log lets you fool yourself
This is the part that hurts to read. With a log, "I'm training" can mean almost anything: random hikes, gym sessions, runs of varying intensity, "active recovery" walks that count for something on the calendar. Total hours add up. The right hours might not be in there.
A plan exposes the gap. If summit day demands 12 hours of vertical-and-descent endurance and the last four weeks have been 60-minute gym sessions and short runs, the plan tells you that, in numbers, against your date. The log just accumulates entries. The honest line: if you do not know whether you are undertrained for your objective, you probably are. A readiness check against your specific peak takes 90 seconds and answers the question without flattery.
When a log is enough, and when it isn't
Honest assessment, not a sales pitch. A log is enough when:
- Your goal is general fitness, not a specific objective with a deadline.
- You already train intuitively well, have a strong base, and self-correct accurately.
- The stakes of underpreparation are low. A missed PB is annoying; a missed summit on a trip you saved a year for is something else.
A log is not enough when:
- You have a specific peak with a specific date.
- The cost of the trip (money, time, leave, partner buy-in) makes underpreparation expensive.
- You have ever turned around short of a summit and wondered if it was fitness.
The decision tree in one sentence: if your objective has a date and a demand profile you can name, you need a plan, not a log.
How to upgrade from log to plan
You do not need to abandon your log. The log is one input. A working plan reads the log and prescribes around it. What changes is the question your tool answers: from "what did I do?" to "what should I do?"
Practically, that means keeping your watch, keeping your data flowing, and layering an objective-aware, date-aware, adapting system on top. That layer is what we built TTM to be. If you want to start with the honest readiness check before anything else, the Summit Simulator turns your peak, your timeline, and your current fitness into a single score and the specific gap to close.
The takeaway
A log is a great mirror. It is a terrible compass. If you have a mountain on the calendar, you do not need to record more. You need a system telling you what to do next, calibrated to your peak, your date, and your data. That is the upgrade from log to plan, and on most trips it is the difference between summiting and turning around.