Re: [Phys-l] treadmill vs open road

["Polvani, Donald G." <donald.polvani@ngc.com>]

Julie Hilsenteger wrote:

> All of us (me and the students) feel it is harder on a treadmill.  I
speculate it is because the surface is a lot different than running >on
ground. When you are stepping on the rubber it, it drops down much more
than the ground does.

> From a very different aspect of this question, I jogged outdoors for
over 30 years (mostly roads with asphalt surfaces).  I now find both
knees have early arthritis.  I had to stop jogging due to the pain in my
knees and now walk for my exercise.  In my jogging days, I only tried
treadmills a few times, but I noticed the rubber of the treadmill's
surface dropping down as Julie pointed out.  It felt harder to run, but
more cushioned.  So, I speculate that running on a treadmill may be
better for your joints than running on hard surfaces due to the
cushioning effect of its rubber surface.  If I had know this 30 years
ago, I might have gladly accepted the (admitted) boredom of a treadmill
in order to continue jogging well into my "senior" years.

Don Polvani
Northrop Grumman Corp.
Undersea Systems
Systems Engineering
Annapolis, MD