Individual run
A planned run can be up to 10% beyond the longest run of the 30 days before it. That counts the long runs planned before it, the way running them would. If you miss one, the runs after it come back down to what you ran.
Long-run growth
Your long run grows by at most 1 mi a week, inside these limits. It stops where your goal needs it: at the long run your race needs (before the race plan starts, at the one the plan starts from), or with no race at 40% of the weekly distance your goal holds. These are app choices, not study results. Cutback and taper weeks are shorter.
Long-run duration
When available, the long run can be up to 10% beyond your longest observed duration, with an outer limit of 2 hours 30 minutes, or 3 hours in a marathon build. These outer limits are app conventions, not proven points where benefits stop. Growth toward them is still held by the other limits.
Race plans
A race plan lasts 18 weeks for a marathon, 12 for a half, 10 for a 10K and 8 for a 5K. Before it starts, you build base up to the level the plan starts from, then hold it. If you already run more, you keep what you run. If you start below that level, the base keeps growing into the plan. Inside the plan, your week grows toward the race's peak: the week your race's long run is 45% of for a marathon, 40% for other races. These lengths and shares are app choices, from common published plans; no study sets them.
Long-run balance
The long run is also at most half of the week it is in, unless your recent longest run is already more. The lowest applicable limit wins.
Weekly mileage
Coach starts from your recent weekly average, leaving out recorded training-stopping pauses. When you did the runs in your last block, the next block starts from the most you ran in 1 week of it. With a weekly target, volume moves toward it by about 10% a week, up or down, and holds there. With a race goal, volume grows by about 10% a week: before the race plan starts, toward the level it starts from, then toward the race's peak week. A target you set, if higher, wins. With no race and no target, volume holds at the level you run now. A week stays within 30% above the level your plan resumes from. A week also holds no more than its runs can carry: every run under the single-run limit, and your long run the longest. When you add a run day, its easy miles join your week once, then the usual step resumes. Every run stays under the single-run limit. This is an app choice: studies link injury to one run much longer than your recent longest, not to how fast the week grows. Cutbacks and tapers reduce the planned distance.
How a week is shaped
Every easy run is at least 30 minutes at your easy pace, or longer if you set a minimum. Your long run stays the longest: an easy run is at most your long run divided by 1.5. Coach plans as many of your run days as the week's distance fills with runs like that, and adds days as your distance grows; the days it doesn't use are rest days. A week can come in a little under its distance, or up to half a mile over, but never over a level your plan is holding. Past 25 mi a week, one easy run is a medium run, clearly longer than the others. These are app choices, not study results.
Run distances
Easy runs and long runs use half steps of your unit, such as 4.5 or 8 mi, or a race distance such as a 10K. These distances are easy to plan a route for. Long runs under 5 mi also use quarter steps, such as 4.25, because a half step there is more than the single-run limit allows. A run never goes over its limit, and the week never goes over its planned total. Hard runs keep the distance of their parts.
What these numbers mean
These are planning limits, not a promise that a particular increase is safe.
Research and limits.
Observational evidence
No big jump in a single run
This keeps a single planned run close to distances you have recently completed.
A 2025 observational study of 5,205 runners found higher overuse-injury rates when a session exceeded the longest run of the preceding 30 days by more than 10%. This is an association, not proof that the threshold prevents injury.
What this does not show
Coach uses this finding to limit individual-run increases. A run inside the limit can still be too much for a particular runner.
Coaching convention
How long the long run gets
Time limits account for how long a run takes, while the weekly-volume limit leaves room for the other sessions. These are app planning choices, and the outer time limits are app conventions.
Zanini and colleagues measured performance determinants after 90 and 120 minutes of running in 14 trained male marathon runners. Several measures deteriorated with duration. The study did not test injuries, training benefits, or a 150- or 180-minute cutoff.
What this does not show
The duration and weekly-balance caps are planning defaults. Research on fatigue during a run does not establish where a training run should stop.
Not supported by evidence
Weekly volume climbs gradually
Coach chooses gradual steps so the plan can build toward your weekly target. These exact settings are app choices, with a separate review needed before changing them.
The same 2025 cohort found no association between its week-to-week distance ratio and injury. That does not establish that every increase is safe, or validate the app’s exact target and warning thresholds.
What this does not show
Weekly percentages are planning choices. Injury studies do not establish an optimal weekly increase.
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