The Treadmill Is A Liar

I went to the gym today to run and I had only packed my indoor gym clothes because of the snowy weather lately here and so I knew I would be on the treadmill today.  After the success of the other day I figured I would aim a little higher because what could make meeting a running time goal easier than gradually increasing the pace.

I got to the gym and changed and took my blood pressure and pulse (43bpm) and then got one of the newer treadmills this time.  I set it to run me at 8.2 mph and endeavoured to complete my 5k (12.5 laps on the machine).  It should be noted that when I ran Sunday morning on the treadmill I set it at 8mph for the first half of the run and 8.1 for the second half and then a mad sprint at the end of about 11mph.  So today i was already setting my pace that no matter what would have me faster than my time on Sunday.

I ran.  I felt good.  and as I neared the end I noticed that setting a pace of 8.2mph or 7:19 per mile, I was going to be over the predicted time of ‘just over 22 minutes for the 3.11 miles I was running (5k).  So on lap 11 I raised the rate to 8.3, then 8.5 for lap 12 and then all out at 11mph for the final half lap.

And then when the time was up i had completed my 5k in about 22:40, a great time to be sure, but somewhere in there is a lie.  Based on the pace alone I should have completed that 5k in under 22:30, yes the treadmill takes a little bit to get up to speed, far longer than I would just running on the road on my own, but I increased the speed for quite a while, about 4 minutes during the last 2 laps and then a full out sprint in the last half lap, that should have more than compensated for the slow speed up of the machine.  Also running the same distance at a higher speed took longer on the newer treadmill (longer than it’s own pace even) than it did on the old treadmill.

So which one is correct?  Which time is more accurate?  I’d have to find a perfectly flat, 5k stretch of road in order to remove the machine from the equation I suppose and really, how likely is that?  Things like this annoy me especially when I am attempting to have a solid grasp on just how fast I am, and an indication of what my improvement is.

It is the same type of thing that bugged me when I was losing weight and on the elliptical all the time.  I would specifically seek out the exact same machine each time I went because I knew then that I was comparing like numbers.  If I went for 50 minutes, on consecutive days, they would be the same 50 minutes, or the same resistance when set to level 14 or whatever.

Either way, I ran the 5k in a record time one of the last two attempts on the treadmill and that is good news.