Your estimated 1RM range is a prediction of the heaviest weight you could lift for a single rep, worked out from how fast you move the bar rather than from actually attempting a max lift.

Every time you lift with the Output sensor, we record the speed of each rep at that weight. Lighter weights move quickly and heavier weights move slowly, and the relationship between the two is close to a straight line. Once we have enough sets across different loads, we can extend that line to find the weight at which the bar would barely move — your predicted 1RM. This is called your Load-Velocity Profile.

Your true maximum isn't a fixed number. It shifts with sleep, fatigue, nutrition and how you feel on the day, so a single figure would suggest more precision than really exists.

The top of the range is your predicted 1RM. The bottom is a more conservative estimate based on moving slightly faster than your slowest lifting speed. On a good day you'd expect to be near the top of the range; on a heavy-legged day, nearer the bottom.

Both numbers are rounded to the nearest whole kilogram or pound.

Open the exercise from your history, top performances, or from the baseline widget after a set. The Performance tab opens by default and your estimated 1RM range sits in the Your Progress section.

The chart above the range shows how your estimate has moved over time, so you can see the trend rather than just today's number. Swipe across it to see what your estimated range was on a given date.

You can change the period using the range selector:

On the longer views, several profiles are grouped into a single point and the best value in that period is the one plotted. This means a wider view can look smoother than the shorter ones — it isn't showing different data, just less of the detail.

The timeline always covers the full period you've selected, even where you have no data for part of it. A gap at one end simply means you weren't training that exercise then.

Alongside the range you may see a change, such as +5 kg. This compares your most recent profile against the earliest one within the period you've selected on the chart.

Because it follows the range selector, the figure changes when you switch between 1M, 3M, 6M and 1Y. That isn't an inconsistency — each one is answering a different question. A small drop over a month sitting inside a large gain over a year is a normal picture during a hard training block.

It only appears when you have at least two separate profiles in the selected period. With one profile or none, there's nothing to compare against and no change is shown — so widening the range will sometimes make a change figure appear where a shorter view had none.

These are two different numbers and they do two different jobs.

Your estimate does not change your programming by itself. If the estimate suggests you've got stronger, you can update your Manually Set 1RM to match — but that's your decision, not something that happens automatically.

You need a few sensor-tracked sets at different weights before a profile can be built. Until then you'll see a prompt rather than a range — keep training with the sensor and it will fill in.

If you haven't lifted with the sensor for a while, we'll show your most recent profile rather than leaving the space empty. Bear in mind that an older estimate reflects the shape you were in when it was built.

Sets you record without a sensor still count towards your personal best, but they can't contribute to a velocity profile.

See also: Athlete Training Zones