Background: I live at 8000 feet but have just come down to sea level to visit family. I decided to hop into a local 5k on Sunday to try to cash in on many months of altitude training. The problem is, most of my fitness has come from running around in the mountains, so I'm lacking in speed. I feel like I'm in about 15:30 shape right now except for the substantial problem of getting my legs to move at 5:00 pace for an extended period of time. Kicking it in feels out of the question. My question is, what kind of tune-up workout tomorrow morning would be most effective to fire up those dormant muscle fibers? Would it be 5k pace work, shorter faster reps, a mix of both? Should I not do a workout at all and just do a bunch of striders the next few days? Thanks for any insight (even if it's to say that what I'm trying to do isn't possible).