Nice. With the Tabata research on short intervals and more evidence that 30s intervals are very efficient in building performance. You workout is also very interesting. It also seems to be that the older one gets, the more important it is to develop and maintain the speed and power.
I am 50 and have realized that speed, power, strength, muscle volume are all very important to incorporate. I do 5x10s hill sprints twice a week, I do heavy strenght work for the legs weekly, I have started to do 5x30s sprints with 5min rest weekly, I emphasize short and fast reps with 30s rest.
I think this workout is very interesting. I have not run a 200 ever, but based on my 30s sprints I could do a single 200 on track with spikes in approx 30-31s.
I might as well try your workout some seconds faster. Apart from the 5x200 and 2x5x10s hill sprints, I do little true speedwork so I might as well take your advice.
I am trying to be fast at approx 15min XC, 3k-5k paces. I am very well fit at threshold and 10k paces, but struggle with running fast at 10-30min