Straight answers about treadmill accuracy, pace, and indoor running. We measure belts with a tachometer for a living, so the numbers here are real.
What the research says, what we've measured ourselves, and four ways to check your machine.
What your watch is really doing indoors, what the treadmill display actually reports, and how to find the real number.
How to tell whether your treadmill needs calibrating, how to check its real speed yourself, and who should actually do the work.
What the 1% incline rule actually fixes, why the belt still feels harder some days, and the one gap no pace conversion can close.
What actually changes from one treadmill to the next, what a small difference costs you, and how to check a machine you have never used.
Where the sensor really sits, the stored number behind the miles per hour on the display, and why steady is not the same as right.
Why your watch cannot reach the belt, what Apple's and Garmin's own calibration instructions really do, and what happens when you calibrate against a display that reads long.
Every way to log an indoor run on an iPhone, sorted by where each one gets its distance. Only one of them looks at the belt you actually ran on.
Usually yes, because a pod reads your foot instead of your arm swing. What you calibrate it against decides whether your treadmill's error follows you.
Zwift shows the speed your treadmill sends it, and says so itself. Peloton never says where its number comes from. Neither one measures the belt.
It dips at every footfall and the motor wins it back inside the same stride. The dip you can feel is almost never where your missing pace went.
Three things open that gap, and the machine cannot settle any of them. Its own pace field is the speed number inverted, so the two can never catch each other out.
What 1.00 and 0.60 actually mean, in both units. Then the reason a machine can show you three different distances at once, and only one of them is your run.
Rep against rep your session is honest, because the belt hands every rep the same error. As a number you take to a race it is not, and changing machines resets even the comparison.
Two percent is ten seconds a mile and four tenths of a mile on an 18 miler. The error lands the same way every session, so the miles add it up instead of averaging it away.
The unit letters settle it in seconds, and the top-speed trick everyone repeats does not work. Then the question knowing the unit still cannot answer.
Every common setting turned into pace, for machines in miles per hour and in kilometres per hour. Then the part no other chart tells you: whether that number is true.
The calibration step copies the machine's distance into your watch. That makes them agree. It does not make either one right.
The number is arithmetic from your settings, not a measurement of you. What the published tests found, and the one number in your run you can actually check.
Your weight feeds the calorie estimate and cannot reach the speed or the distance. Skip the box and the machine quietly assumes a person of about 150 to 155 pounds. The number your training runs on has no box at all.
Everyone presses 6.5 and no two belts have to agree. Each machine turns the number into belt motion its own way, and no documented service schedule ever checks whether the speed on the display is true.
The 3.0 is a setting the machine was asked for, and the workout has no outside check that would catch a slow belt. The studies behind it took the display at face value too. Walking speed is the easy one to measure.
Every belt gives a little under a footstrike and you never feel it. A slip is the belt losing its grip under your foot, and the display cannot tell you. One slow-walk test tells a slip from the normal dip, and what to report to whoever fixes it.
The makers' own schedules do not agree with each other. What is weekly, what waits for a technician, why lubrication is the trap, and the one thing no service ever checks: whether the speed on the display is the speed of the belt.
The 1 percent incline settles the effort. The distance is a different kind of number: outdoors your watch measured the ground, on the belt the miles come from a setting nothing checks, and a winter block can drift on it without you knowing.
The goal-time-to-speed table for every common marathon time, the incline rule's real tested range, and why the pace you rehearse for months is a setting nothing on the machine checks.
A predictor multiplies whatever pace you feed it, error included. The pace from a treadmill time trial is a speed setting nothing on the machine checks, and a belt a few percent off hands you a race goal your legs never earned.
Your treadmill never measures the slope you run on. It moves the deck from its own zero point and shows the grade you pressed. Here is what two points of grade cost a hill session, and how to check the deck with your phone.
Your virtual 5K time is how long the display took to reach 3.1 miles. A road course is measured with a checked wheel before race day. Here is what a small gap does to the time you submit, and the 3.10 trap.
No. A tilted belt carries you the same mile as a flat one. Incline adds climb, about 525 feet a mile at 10 percent, and that climb is only as real as the deck's grade.
Strava never measures your treadmill run. It logs what your watch, GPS or synced display sent it, and none of those measured the belt. Here is where the number comes from and what to do before your next run.