oooo. if you can read it easily enough it works really well! i did it for my hsc. best hour of english study i have done in my life :P
i think the day before one of my exams i actually went for several runs, taking a different essay each time. just coz it actually forced me to read it :P haha.
It's something I used to do quite a bit in my later years of school, too. Apart from being a good use of time it definitely helps train your concentration on the run.
yeh i rekon, i was just super stupid and made the type to small :P