I don't know of any plant that has square roots, it's just not natural.

Interesting, but I question the accuracy. On Collegiate Loop this summer I could gain 4,000 feet over 12 miles. 4000 x 2 x 12 = 96,000. Square root of that is 309.8. Well beyond very strenuous (200). Never mind the altitude. I always thought I was a slow hiker. But perhaps I am not so bad after all.

I am all for a formula to try to quantify a rating, but there are so many variables that have left out.

Astro correctly brings up one, Altitude. It makes a huge difference.

I will bring up another, mud and roots! Try hiking the Northern half f the Long trail sometime

OK Cafe members, what other variables are missing?

Attitude. Some days you're just going to feel stronger than other days.

I didn't click or read it....but are ROCKS included? And how do you quantify them.... Mud would be another. Ver-mud shoe-sucking mud versus our Texas Black Clay (also called gumbo) versus our Texas Red Silt (It's called The Red River for a reason).....

I flashed to the scene in Dead Poet's Society where Mr. Keating is showing "the boys" the Doctor Pritchard graph to chart poetry.....

How about weather? If it's too hot or too cold it makes it harder for me. Heat has more affect on me than the cold. Mid 60s is ideal for me. Of course then there's wind, rain, and snow.

I use the MF scale to rank climbs and descents. Simply count the number of times I yell "Mutha........." during the effort. Works for me.

For us, my wife, she can not negotiate any trail the requires her to step up or down, over an obstacle, and place he foot on a non level surface. A trail I can negotiate without breaking stride could easily take 15 seconds per step, which is a pace that is not practical for mor than a few dozen yards.