Downhill Treadmill

There are considerable benefits to training with downhill running.  Of course, the best way is to have lovely long mountainous trails in your neighborhood and run in the real world. Living in Dallas, a modified treadmill may be as good as it gets at times.  The best downhill discussion in a concise form is on fellrnr’s site so I will reference it here

Today I modified my treadmill for downhill running with two cinderblocks.  A cinder block is 8″ on the short dimension.  I used two ‘half sized’ cube shaped blocks that were 8x8x8. Doing the math with my treadmill geometry, I guessed that it would give me an 8 degree incline, which equals a 14% grade.  My treadmill will elevate up to 15% grade, thus, a maximum elevation on the treadmill puts it about a percent head up.

Sure enough, when I put the blocks under the treadmill and measure with my smartphone level app, it gives me 14% and when I set the treadmill incline to 14%, the treadmill measures as flat.

downhill treadmill 1

downhill treadmill 3

downhill treadmill 2

By the way, the other structure is a treadmill desk, a great investment, or you can build your own.

With my first run on the modified treadmill – a few thing of note.

  • This setup is very stable
  • If you step or fall off the back, you have a longer way to go
  • It feels really strange for a treadmill, but pretty much like running downhill
  • Realize that with a downhill mod, you are making the treadmill do lots of work to lift you.  I have a used commercial treadmill that is heavy duty in every way and at only 160 pounds, I was able to cause a speed error shutdown of the treadmill at the end of my intro workout when I cranked it to -14% grade at 9 mph.  The treadmill was only able to go 8.5 mpg and after about half a minute it shut down with a ‘check speed’ error.  Totally expected this.
  • If you beat up the ends of your toes on a long ultra and lose toenails, you may be able to work on finding better sized shoes or lacing or tightening your shoes better with this rig.  After just 30 min at various downhill settings my toes were starting to get beat up.  They need this at a running store to test for shoe fit!


With some shared ideas from Dallas Maker Space I’m going with an automotive scissor jack to elevate the tail end of this treadmill.

scissor jack

At 5000# capacity this is overkill in terms of lift capacity but I chose this one over the 1.5 tonne version (Harbor Freight) because of the heftiness that should provide more stability in terms of fore / aft, front / back movement.

My first thought was to wire weld a steel plate to both the top and bottom and fit it to the underside of the tail of the treadmill.  However, I realize that I can probably use wood for the job and that may be easier, although at the expense of a thicker apparatus.  Need to find a suitable gear motor to interface to the jack.


OK, I’m a dummy.  I spend half a day looking for and configuring a suitable gear motor to attach to this thing to automate it.  Then I come across this thing.

motorized scissor jack

Yeah, there are tons of these for sale already.  The thing is basically built for me.  Now I just need to buy one and interface mechanically to the treadmill.  Well, always handy to have jacks for farm and automotive use, so I’ll hang onto the one from Horrible Freight.