Charlie,
After reading Structure of Training I have a question about building up the work capacity during the GPP. You write that once you build up to a volume max then a simple example might look something like this: 4x[4x60] with increasing acceleration distances and decreasing reps as the phase progresses.
My question is how would one build up to that initial volume during the GPP? Would it primarily be with 20-30 accelerations to acclimate to speed training and then adding the 20+40 type runs in the SPP as described above and going from there?
6 x 80 m [or 2 x (3 x 80 m)] (hill),
2 x (4 x 60 m) (track),
3 x (4 x 60 m) (track),
4 x (4 x 60 m) (track)
progression work? Although I suppose not all athletes would necessarily (want to) reach the latter volume. A fair amount of acceleration work will probably be done by this point, with the intensity limit of the 60s not exceeding the acceleration distance established.