Treadmill pace versus outside running

npurdy1112 wrote:

Streaker wrote:

I agree, my Stryd is very accurate on the track - I’m taking for granted it’s just as accurate on the mill.....

Must be nice haha! My Stryd is inconsistent and inaccurate. Calibrated a pair of shoes on the track via their website info in June and by fall the calibration factor somehow was now 2.5% off. Same track, shoes, line, everything. Have tried to exchange for a new unit so they can look into issues but they say, "maybe a future update will fix".

Hmmm...my calibration is set to 100% and I find it’s at least as good as gps. Don’t notice any discernible difference while using different shoes. Hope the issue with yours gets worked out.

To some extent, I find it difficult to understand how a treadmill can be very inaccurately calibrated. The belt is a certain length. As long as the machine can count how many times the belt has gone completely around, and as long as it has a clock, it can calculate the total speed.

Thus, yes, the heart rate gadget may well be way off, and the current speed might not be entirely correct if it is an instruction rather than a measurement, but surely the final stats should be accurate?

I've run 1000km+ these past few months on a treadmill (NordicTrack C2950) at all sorts of speeds and inclines and I have calibrated it with a measuring wheel, high speed video, foot pods, treadtracker wheels and cadence from watch etc. Bottom line, for me, the speed the treadmill shows is always under, yes under, what it actually is. More and more at higher speeds and more and more the further you run. I could show you the XLS and all the different data files I have but suffice to say, for me on my treadmill, when I set it at 12-13-14kph (my Z1-Z2-Z3 paces) it'll range from 12-12.4, 13-13.5, 14-14.6 kph throughout the run. Basically 3-4% under by the end.

Well, treadmill belts are not always moving at a constant speed. They slow doing upon impact, and then the motor speeds up the thing to get back to the supposed average speed set by the user. So the values you see on the display are more of a calculation/estimation than it is a pure measurement.

One way to see this is the incline. If you go from 5% to 0%, the display will stop accumulating elevation, although you are technically still running at a positive incline.

This is what I personally suspected with my NordicTrack T12, that it runs faster than the display and the Runn unit, unlike my Stryd (factory calibration 100%) seems to agree, but I need to do more testing. Nicer weather has let me use the mill less these days so I can't tell for sure.

Are the slatted treadmills more accurate?

Less bouncy ? Maybe less fun to run on?

jiggymeister wrote:

Well, treadmill belts are not always moving at a constant speed. They slow doing upon impact, and then the motor speeds up the thing to get back to the supposed average speed set by the user. So the values you see on the display are more of a calculation/estimation than it is a pure measurement.

One way to see this is the incline. If you go from 5% to 0%, the display will stop accumulating elevation, although you are technically still running at a positive incline.

My point was that all this is taking out of the equation if the machine calculates distance as number of times belt has gone around, and calculates speed using that measurement of distance and its clock. Thus, yes, the values on the screen at any particular time may not be accurate if they are taken as instructions from the user to the machine, but the overall stats should be accurate.

King Tiger wrote:

Are the slatted treadmills more accurate?

Less bouncy ? Maybe less fun to run on?

I have a slatted treadmill. Cant comment on accuracy. But there is no belt to tension like a traditional. The motor gear and belt are both "toothed" so there is no slippage. Less bouncy, yes definitely. I would say more fun to run on. Much more smooth and quiet.

I have never tried one, can't comment.

npurdy1112 wrote:

King Tiger wrote:

Are the slatted treadmills more accurate?

Less bouncy ? Maybe less fun to run on?

I have a slatted treadmill. Cant comment on accuracy. But there is no belt to tension like a traditional. The motor gear and belt are both "toothed" so there is no slippage. Less bouncy, yes definitely. I would say more fun to run on. Much more smooth and quiet.

I know Woodways are supposed to be the gold standard, but I find them way too soft. You don't get the some bounce from the entire deck the way you do on conventional treadmills, but the slats themselves are so squishy that they just sap your energy.

+1