Building Tempo runs, start fast and lengthen, or work up in distance and gradually cut pace?

I assume by shorter and faster initially, you may be describing cruise intervals or even a fartlek type training bout? If so, I have always introduced a phase of cruise or subdivided tempos, because maintaing a longer tempo at x pace may just be incorporated into a progression run on a different day. At least the cruise or shorter tempo enables the athlete to focus and build the concentration of effort, and separate out the hard efforts into component parts until greater fitness is achieved to maintain hard pace for longer, continuous periods.

I think he's referring to doing something like 4 miles @ 5:30 or 8 miles at 5:30. should he do 4 miles at the pace or 8 miles at like 5:50.

I'd say pick a distance, ex 10 miles..and cut the pace through out the season. It's a great way to measure progression while still getting a great deal of work in.

I have usually started with shorter runs (ex 4M)at current Half Marathon pace and gradually worked up to a longer distance at the same pace. As I got fitter, the pace naturally felt easier and I could maintain it longer. I normally would not go longer than 7 miles for a Tempo run, so once I was comfortable with that pace for 7M, I would start to cut down the pace (more toward goal HM pace).

I think doing it the other way (starting at a faster pace) would result in you running beyond your threshhold on your earlier sessions. I am no science guy, so I have little to support why I do this. It is just how I run.

I think when you move from a longer, slower run to an actual threshold pace tempo run, you are actually changing the workout. Remember, the purpose of the tempo run is to work at threshold pace, and to stress the body's lactate clearing ability.

Not to be wishy-washy, but the longer "tempo-type" run (which may just be a long, relatively hard, steady effort) does have a purpose, and is certainly useful psychologically to improve mental toughness, and physiologically to build energy system capabilities gradually to adapt to that longer distance. But it is a different type of workout.

If you are actaully concentrating on the purpose of the traditional tempo, then you have to establish the threshold pace and work at that pace, not slower. Early in the season, it may be more beneficial to break the tempo via the shorter cruise intervals to ensure you can do more mileage at that pace, and then build the tempo bout mileage or distance to 20-minutes plus as you improve fitness.

If you search around here long enough you will find,

"In Canova training I refuse to choose between EXTENDing the distance at the same pace and to INCREASE the intensity in the same distance. These 2 parameters work together. During winter my main aim is to build ENDURANCE and STRENGTH. First, I use a lot of long run at different speed:

a) We start with 40' going in one week at 1 hr at comfortable pace (for example, in the case of an athlete running 14' in 5000 or 3'45" in 1500m, a pace of 3'40" per km or 5'53" per mile)

b) After this short introductive period, we move in 2 directions :

1- We extend the distance at the above pace till 1 hr 30' in the next 3 weeks

2- We try to increase the speed of 1 hr using the system of PROGRESSIVE RUN (for example, the last 20' run at 3'20" or 5'20"), extending the fast part till the full hour is at the same fast pace.

3- At the same time, we start to put in the program some session for STRENGTH, combining exercises of reactivity, technical exercises and short sprints uphill, carried on at the maximal intensity (otherwise, it's not possible to develop strength).

c) When we are able to do this, we have another period where we develop our training in this way :

1- If the athlete is a specialist of 10000m / HM, his long continuous run at the pace of 5'50" per mile can be extended, once per week, till 2 hr. If is a specialist of 1500 / 5000 or steeple, can remain of 1 hr 30' using some final progression.

2- Once per week, there is a LONG FAST RUN, that in the case of a runner of 10000/HM is between 20 and 25 km, and the athlete try, week after week, to run a little bit faster. In the case of an athlete for steeple / 5000 the distance is between 15 and 25 km, for a specialist of 1500m between 12 and 18 km.

3- These 2 different training are in the program every week, with 3 full days of interval in between (for example, on Monday the longest, on Friday the fastest).

4- In the middle (in this case, on Wednesday) we start to work for SPEED ENDURANCE, alternating FARTLEK (sessions lasting about 1 hour with mixed distances, for example

6' + 1' + 5' + 2' + 4' + 3' + 3' + 4' + 2' + 5' + 1' + 6' fast (42' global fast work) with 2' easy recovery (22') giving a total time of 1 hr 04'), or long intervals on track (for example, 3000 + 2 x 2000 + 5 x 1000 + 6 x 500m, recovery after 3000 and 2000 in 3', after 1000 in 2', after 500 in 1'30")

5- During the other days (Tuesday, Thursday, Saturday) we use long and easy run (never less than 18 km, till 25 km, at comfortable pace) and exercises for STRENGTH, extending in order to increase the STRENGTH ENDURANCE.

d) Only after, when the AEROBIC BASE is consolidated, we start the real training of speed.

When we start with this, we can’t use a weekly program, but our microcycle lasts 2 weeks, because NEVER WE GO TO REPLACE THE LONG RUN, BUT WE GO TO ADD SPEED TO THE PROGRAM ALREADY USED. One of the most important points is : NEVER WE HAVE TO LOSE WHAT WE WERE ABLE TO BUILD BEFORE. Training is not to replace, but to ADD."

All great information, thank you all for the contributions.

And I should have clarified in my post, but you all seemed to hit on parts of what I was getting at.

I like the recommendation to start with Tempo segments - cruise intervals and then basically connecting the dots while working towards building to a continuous tempo run. When coming off of a base period and building on tempos, it sometimes feels as if I am running slower than what I am capable of in an attempt to get in the amount of time and distance for a continuous tempo, when in fact I am probably not strong enough yet, and should focus on the tempo segments of cruise intervals at a faster pace, and then eventually work to a continous run.

In similar fasion and much like the Renato post and the above example I had kind of had a feeling that I should take a methodical approach and start at say 10 minutes Tempo at a reasonably challenging pace, and then just slowly add on a certain amount of time each week, gradually lengthening. This would be a means of my body getting used to the pace early on in training.