I wrote about using longer intervals to work on speed, but conversely you can also try using shorter intervals to work on strength!
When I first moved to Utah, I found it near impossible to run 8-10 x 800s like I used to do in Okinawa, so decided to give 400s a try. After a couple of workouts I found that I could use them as a strength workout by keeping the pace moderate, shortening the recovery to only 30 seconds, and increasing the number. I actually did one 20 x 400 workout before Boston. It sounds hard and it was, but no more difficult than the 10 x 800 workouts I was managing in Okinawa.
The key, of course, is not getting carried away with pace on the early ones. They take some getting used to but offer a nice break from the usual long for strength formula, especially at altitude!
(C) 2007 Dave Elger all rights reserved