treadmill math

here in the midst of taper week there isn't much going on as far as actually running. i've spent some time browsing the runner's world recently-renovated-and-still-full-of-bugs forums, and i'm reading both pfitz's "advanced marathoning" and daniels' "running formula" to figure out what training regime is up next. i need something hardcore that will help me get way faster. so far, they've both been good reads and i know either route will be beneficial. i'm kind leaning towards daniels' a little more, but the laziness in me likes that pfitz provides clear-cut schedules. luckily, i have a few days to read more, mull over it and decide.

i put j's engineering degree to good use with a scientific experiment on my treadmill so we could figure out what the 'real' speeds are. i know i'm not that fast, but i know what my easy pace is on average and it was not matching up to what the treadmill was reporting.

first, he measured the length of the, um, running strip thing in inches (52.5") and then multiplied it by 2 since you can only measure half of it, unless you want to flip your treadmill over and measure the underside of course but multiplying is easier (105"). he also marked a spot on the running strip to help track each rotation. then he set the speed on the treadmill, to seven different speeds ranging from 5.5 to 8.5, and timed 20 rotations (using the spot) at each speed. he did this 3 times at each speed to ensure the most accurate data of course.

now for the boring equation part:

# of rotations * length of running strip = distance (in)
20 * 105 = 2100 in

distance / time it took to reach 20 rotations = speed (in/s)
2100 / 16.36 = 128.36 in/s
(for "7.0" setting)

(speed (in/s) / 12 / 5280) * 3600 = speed (mph)
(128.36 / 12 / 5280) * 3600 = 7.29 mph

7.29 mph translates to an 8:13.9 min/mile
which is kind of like the treadmill telling you your speed is 7.0 mph (8:34.2 min/mile)

of course you do this for each of the rotation-timings and then figure out the average at each treadmill setting. on my treadmill, the actual speed was about .20-.30 mph faster than what the treadmill says. i'm just glad the results came back in my favor! i'm not as slow as the treadmill tells me i am. :o)

belated congrats to all you other lottery winners and african trust-fund inheritors out there. who knew we were all a bunch of millionaires spending our days blogging about running...

monday (1/5) pm run: 4.4 miles, 41:29 (9:25 avg pace), avg/max hr (143/164)
tuesday (1/6) pm run: 4 miles (2xmile@7:16), 33:01 (8:15 avg pace), avg/max hr (172/197)