[email hidden] (Opticreep) wrote in message news:<[email hidden]>...
Quoted message said:I've always wondered if there was a significant difference between
using a treadmill and actually running (or jogging) around a track.It seems to me like a person on threadmill doesn't exert as much
horizontal force as a person actually running around a track. In
other words, a threadmill guy could basically use most of his energy
hopping up and down while the machine moves the tracks under him.
A mass that is not acted upon by an external force continues to move
in a straight line at the same velocity. You don't have to exert a
force on an object to keep it moving. Energy is spent in running only
to compensate for friction: friction between your feet and the ground,
air drag, and internal friction within your body. Even if you run in
spikes, with a tailwind that matches your speed, so that there is no
ground or air friction, energy is still required just to move your
legs. Each of your legs is like a pendulum. In order to control the
swing of an oscillating mass so that it follows a desired motion, you
have to dampen its motion, thereby wasting energy, and put in extra
energy. This is, for instance, the big reason why subwoofer
loudspeakers require so much wattage. They have to be dampened so that
they follow the input waveform rather than oscillate on their own, and
that damping wastes most of the input power.
These are what makes treadmill running different:
- no significant air resistance, except that of your limbs disturbing
the air; basically the same as running with a tailwind that matches
your pace
- no acceleration of your body mass (necessary for practicing sprints)
- consistent running surface that is springy
- no cornering
- no lateral inclining unless you prop up the treadmill.
- no downhill running, unless you prop up the treadmill.
- tightly controlled pace that must be adhered to to stay within
the narrow box: run a little faster, and you hit the dashboard;
fall behind, and you are ejected from the belt; take some
sloppy lateral steps and you hit the side rails.
- controlled indoor temperature and humidity.