Aerobic Volume

The Volume number on the team training page puts running mileage and cross-training time into one unit, so six hours in a pool and twenty miles on the road can be read side by side.

The most useful thing to know about it is this: a run contributes its distance in miles, unchanged. So a pure runner’s volume equals their mileage, and any gap between an athlete’s volume and their mileage is exactly their cross-training.

An athlete showing 15 miles and a volume of 35 did twenty points of something else that week.

What one point is

One point is a mile of easy running, taken as ten minutes of moderate aerobic work.

Points are deliberately not called miles. Forty points is not forty miles, and the number is not a distance — it is what that week of training was worth in a unit a coach already has intuition for.

Running

A run contributes its recorded distance in miles. No time conversion, no climb bonus.

That trades consistency for legibility. Adding a climb term to runs would be defensible on its own, but it would break the equality above for every athlete, including ones who never cross-train. A run with no recorded distance contributes nothing.

Everything else

Every other activity converts time into points at a rate set by its type:

points = minutes ÷ rate

The rates are fixed rather than calculated per athlete. The number is meant to be read within one athlete over time, and fixed rates keep it stable as their fitness changes.

Unrecognised activities — skiing, rafting, snowboarding — are rated at walking pace. That is low on purpose: a three-hour ski day should not be able to look like a spike.

Climb

Walking, hiking and cycling add a climb term, because on those three the climbing is where the work is. Roughly 1,000 ft of climb is worth one extra point.

Two limits apply:

• Climbing can never out-earn the time spent. The climb bonus is capped at the activity’s own time points, so an hour walk worth 2 points can earn at most 2 more.
• Elevation has to be credible. Gain is ignored unless it is at most 25% of the distance covered. Real mountain days measure 6–14% grade; barometric drift on a cheap sensor produces figures like 74% and 123%, which are not possible over the distance recorded. An activity with no distance at all cannot be grade-checked, so its elevation earns nothing.

Running does not use the climb term.

Strength work

Where the watch reports an activity as strength training, it is excluded — it is real work, but it is not aerobic volume.

Where the watch does not say, the activity counts at the gym-cardio rate. The generic buckets that watches use for indoor work are predominantly elliptical sessions in practice, so the ambiguous case is resolved in the athlete’s favour rather than against it.

The watch left running

An activity longer than two hours whose average heart rate is under 95 bpm is treated as a watch someone forgot to stop. It drops to the unrecognised rate of 30 minutes per point rather than being thrown away, so a misclassification costs a factor of three instead of the whole session.

Both conditions are required. A long activity alone is unremarkable, and so is a low average heart rate alone. A missing heart rate never triggers it.

Rounding

Volume is summed raw across the whole week and rounded exactly once, at the end.

The threshold is 0.8, not 0.5 — a point has to be nearly earned before it is shown. So 12.79 displays as 12 and 12.81 displays as 13.

Activities are never rounded individually. Three 25-minute walks are 2.5 points together; rounded one at a time they would each be 0 and the day would read as empty.

A week, computed by hand

The week displays as 35, against 15.2 miles of running. The 0.377 remainder is below 0.8, so it does not round up.

What this is not

• Not a training-load model. There is no TSS, no intensity factor, and no accumulated fatigue. It measures how much aerobic work a week held, not how hard it was.
• Not calibrated per athlete. The rates are the same for everyone.
• Not for ranking athletes against each other. Two athletes with the same volume did not do the same training, and the number is not evidence that one worked harder.
• Not precise enough to prescribe from. It will not tell you what next week should be.

What it is for is noticing, within one athlete over time, whether the week was real work — particularly for an injured athlete whose mileage has gone to nothing while their actual training has not.

For why the rates are what they are, and what the roster data looked like before they existed, see What Six Hours of Cross-Training Is Worth.