Tempo Thursday

This Thursday is Tempo Thursday.  Sorry to change things up a bit, but here goes nothing...
The tempo run is something that is talked about in running and suggested in training plans for all distances, but it's an elusive creature to most runners.  The run down of the tempo is that it is a kind of 'race simulation' and it is supposed to make you feel as though you are working at a pace that will be close to what your goal for a given race is.  The tempo is particularly great for longer races (10k plus) because those races require running at a certain pace for a long period of time, while in 5k's you tend to run more of an 'all-out' kind of race.  This is not to say that you don't 'pace' yourself for a 5k or 5 miler, however, there is essentially less time at pace and more time at the initial 'get off the line' and 'finishing kick'. 
So here's how to do a tempo-style workout for let's say a half marathon at 8:00 pace...
Run 1 mile warm up (or 2 miles, or whatever you need to get yourself going)
Run at approximately 8:05-8:15 pace for at least 6.5 miles (approximately half of the distance of the actual race) while trying to more to keep the miles at a consistent time rather than digging a hole with early fast miles and them slacking on the later miles.  It is better to run the first few at 8:05 and then if you have to slow down to do so on the back half of the workout.  The idea behind the tempo is to make the goal speed (or slightly slower) your 'natural' pace rather than struggling for the entire race.

If you are able to, do another set of about 3.25 (or half-ish) of what you did before with maybe a mile jog/active rest in between.  Try again, to keep the same pace of 8:05-8:15.  These last few miles should be difficult.  I always try to end a workout like this with some striders, 100m easy sprints, or hill sprints (find a hill that is about 50 meters and run up and down about 10-15 times).