As a masters age athlete (36), with a full time job that has me on my feet quite a bit, I’ve used a few of the variations listed in this thread with success.
The first variation listed was this:
Day 1: Speed, plyos, weights (Hi day)
Day 2: Tempo + other general fitness work (Low Day)
Day 3: Off
Day 4: Repeat Day 1
This worked well for me as long as I did not work too hard on the tempo day. I think I started at ~1000m and worked up to something like 1500m. If you start to feel a bit worn down, take an extra off day.
If you find yourself frequently needing extra off days, then try this:
Day 1: Speed, plyos, weights (Hi day)
Day 2: Tempo + other general fitness work (Low Day)
Day 3: Off
Day 4: Speed, plyos, weights (Hi day)
Day 5: Tempo + other general fitness work (Low Day)
Day 6: Off
Day 7: Off
With this plan, you can vary the volume on your tempo days. Make the volume of tempo on Day 2 lower and the volume on Day 5 higher. With the extra day off on Day 7, you’ll still start your training week fresh. I actually did some pretty hard tempo workouts on Day 5 of this setup (stuff like 10 x 200m with fairly short recoveries) and still felt fresh two days later.
I’m currently emphasizing weights and doing the following:
Day 1: Speed + Lower body weights
Day 2: Tempo + Upper body weights
Day 3: Off
Day 4: Speed + Lower body weights
Day 5: Tempo + Upper body weights
Day 6: Off
Day 7: Off
If you do this, you’ll want to cut the volume of tempo you are doing to accomodate the weight work done after.
Also, one other quick note. When doing the above, I used speed workouts similar to what was on the GPP DVD, but I have never even tried to do the full volume of speedwork. This may be because I am an older athlete, but I was never able to do more than maybe 1/2 or 2/3 of what was prescribed. I was always under the impression that those workouts were designed for a fairly high level athlete and should be adjusted to accomodate your own needs.