Target Paces Are Estimates, Not Rules

When you open a workout in rslts and see a target pace next to a rep, it is easy to read that number as a rule. It is not. It is an estimate built from one race result and a couple of well-known formulas, and it does not know anything about the hill in the middle of your loop or the fact that you slept four hours.

I want to walk through how those numbers get calculated, why they sometimes come out a little fast, and why slowing down to finish a workout is usually the right decision rather than a failure.

Where the Numbers Come From

Your zones are anchored to a single race result. The system picks your best recent race automatically from any supported distance of 1500m or longer: 1500m, mile, 3K, 5K, 8K, or 10K. An 800 is used only if it is the sole distance you have raced — see why your 800 was lying about your training paces for the measurements behind that. From that one performance, it derives four pace targets using two different models.

Easy running is not in that table on purpose. Easy sits below all four of these, so easy days should be slower than the marathon anchor, not right on it.

That is the whole calculation. One race, two formulas, four numbers. There is no measurement of how you actually felt during any workout, no lab test, and no adjustment for the course you are about to run on. For more detail on how the zones map to chart colors, see the pace zones documentation.

Why the Targets Can Still Come Out Too Fast

The two Daniels numbers are not the aggressive part. Marathon at 75% and threshold at 83% are the lowest fraction of VDOT in each of their bands, which puts them at the slow, conservative edge of the zone rather than the middle of it. Each one is a lower boundary: the zone runs from that pace up to the next one. So if your threshold number already feels too hard, the model is not what is making it hard.

The 5K and mile numbers are a different kind of estimate. Both are Riegel race equivalents, which means they describe what you could race at that distance today, not what you should be repeating in a workout. Reps at your mile number are reps at all-out mile race pace, and that is a genuinely ambitious thing to ask for in a training session.

Underneath both of those sits the anchor race, and that is usually your best one. A peak track race in perfect conditions produces faster zones than an early-season race or a cross country race on a muddy course. If your zones came from the fastest day of your season, they describe the fitness you had on the fastest day of your season. Most training days are not that day.

None of that is broken. It just means the numbers describe you on a good day, on a fast surface, at the sharpest point of your year. Hitting them exactly is not the bar you should be measuring yourself against.

The Track-to-Cross-Country Transition

The place this shows up hardest is the first few weeks of cross country.

Track season ends with the fastest race you have run all year, so that race becomes your anchor. Then there is a break, which is exactly what a break is for. When you come back and start the fall build, the zones on your screen are still describing the athlete who ran that peak race in May, sharpened and rested and on a fast surface. You are not that athlete in the first week of August, and you are not supposed to be.

The top end drifts furthest. Your 5K and mile zones are Riegel conversions of a sharp track race, and early cross country training is usually the least sharp part of the year: more volume, more aerobic work, more threshold, and much less pure speed. Those top two numbers are estimates of a quality you are deliberately not training right now, so they are the ones most likely to feel out of reach. If a fall interval session leaves you well off the mile number, that is often the training block doing what it is supposed to do rather than a sign that something is wrong.

Threshold usually stays the most usable of the four through the transition, but it can still feel hard early. It was calculated at 83% of a VDOT you had at your peak, and you are coming off a break. The effort is right even when the pace is not there yet.

Then add the course. Cross country is grass, dirt, and hills, and your anchor was probably a flat track. Stacking a stale anchor on top of a slower surface is why so many athletes feel like they lost more fitness over the summer than they actually did.

What the Estimate Does Not Know

The biggest gap between the number and the day is usually where you are running.

If your zones are based on a track race and you are doing the workout on a grass field with rolling terrain, you will be slower. Not slightly slower on the uphills and even again on the downhills, but slower on average, because soft ground and elevation change cost you time that flat rubber does not. The same is true for gravel, trails, wind, heat, and altitude. The formula does not see any of it.

This shows up clearly when you look at the charts after a workout. A rep that dips in the same spot every single time is almost never a fitness problem. It is the course asking the same question at the same place. I wrote more about reading that in how to analyze a workout.

So when you take a track-derived target onto a hilly grass loop, the honest adjustment is to run the effort the workout is asking for and let the pace land where it lands.

The Day You Are Actually Having

The other half of it is you, and the estimate does not know anything about your day either.

Bad sleep, a meal you skipped or ate too close to the session, a long school day, a hard shift at work, a weekend that included a family picnic and a football game — all of it affects what you can produce that afternoon. A pace that was completely reasonable on Tuesday can be genuinely out of reach on Thursday, and the number on the screen will not have changed at all.

That is worth saying plainly to younger athletes especially: the target did not move, but you are allowed to. Being slower than the estimate on a given day is information about the day, not a verdict on your fitness.

Backing Off to Finish Is a Good Outcome

Here is the part I most want people to take away. If holding the target pace means you fall apart halfway through the session, and easing off by ten or fifteen seconds per mile means you complete the whole thing under control, the second version is the better workout almost every time.

Most sessions have a purpose that is bigger than one number. A threshold workout is asking for controlled, repeatable, comfortably hard running. If you have to grind to hit the pace on rep two, you are no longer doing a threshold workout — you are doing something harder that will cost you more to recover from and teach you less. Backing off to the effort the workout was designed around keeps the session doing its job.

The thing to protect is the shape of the workout, not the numbers written next to it. Every session has a shape that carries its intent: reps that stay even across a threshold set, reps that get faster as they get shorter, a float in the middle that stays honest, a last rep you can still accelerate on. That shape is what makes the workout teach what it was designed to teach. The paces are scaffolding for the shape, and scaffolding can move.

Shifting the whole set ten or fifteen seconds per mile slower and keeping the reps even is still a threshold workout. It did exactly what a threshold workout does. Hitting the prescribed pace on the first two reps and then falling off a cliff for the rest is not, even though two of the splits matched the target. The workout with the right shape and the wrong numbers is worth far more than the workout with two right numbers and no shape left.

That is also an argument for adjusting early. If it becomes clear in the warmup or on the first rep that today is not a day the target is available, reset the pace for the whole set right then. Deciding on rep one is how you keep the shape. Defending the number for two reps and then surviving the rest is how you lose it.

The question I ask when I look back at a workout file is not whether every rep matched the target. It is whether the changes in pace were a problem or a decision. Deciding in advance to run a hilly grass loop at threshold effort instead of threshold pace is a decision, and it is a good one.

When to Change the Estimate Instead

If you are consistently missing the targets on ordinary days, and the terrain and conditions do not explain it, the estimate itself is probably the thing that is wrong. That is fixable. On the Workout Paces page, linked from your athlete home page, you can:

• Pick a different anchor race. Choose any supported result from your history instead of the auto-selected one. The best race of your life is not always the right anchor. Pick the race that reflects the fitness you want to train at right now.
• Enter paces manually. Type in your own marathon, threshold, 5K, and mile targets. Manual entries take precedence over the calculation and apply across every chart immediately.

Either way, set an Effective from date rather than treating the change as retroactive. Zones are stored with a date and every activity resolves the zones that were in effect when it happened, so starting a new set of paces at the beginning of your cross country block leaves your spring workouts colored by the paces you were actually training at. You keep an honest record of both seasons instead of rewriting one with the other’s numbers.

Changing the anchor is not lowering your standards. It is making the number describe you more accurately, which is the only thing the number was ever supposed to do.

Final Thought

Target paces are a starting point for the effort, not a test you pass or fail. They come from one race, two formulas, and no knowledge of your course or your week.

Run the workout the way it was meant to be run. If that means backing off the number to finish the session under control, back off the number. A completed workout at the right effort is worth more than a partial workout at the right pace.