Coach

From the Coach guide

A longer week and a longer run are different changes.

Limits on individual runs and weekly mileage keep increases in check.

Individual run

A planned run can be up to 10% beyond your longest run in the previous 30 days.

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.

Long-run balance

The long run also stays within a cap based on half of the recent weekly volume supplied to the planner. The lowest applicable limit wins.

Weekly mileage

Coach starts from your recent weekly average, leaving out recorded training-stopping pauses. Later base-volume steps grow by about 10%. If you set a weekly target, steps move toward it and hold there. Generated weeks stay within 30% above the starting average. Cutbacks and tapers reduce the planned distance.

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.

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-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.