In reply to Paul Crusher R:
Also, to respond to the "training after having kids" part of this, I think Paul Crusher R. makes a really great point - you have to figure out a way to train in short sessions, but this can actually be a benefit, as it keeps you focused.
Two that I like (each takes less than 45 minutes).
1) warmup for five or ten minutes, then pick 4 problems of increasing difficulty (e.g. v4, v5, v5, v6). Do problem one 4 times in a row with no rest. Then rest 4:00. Then do problem two 4 times in a row with no rest. Repeat that for all four problems, then do some core work at the end (leg lifts, crunches, whatever you like).
2) warmup for five or ten minutes, then do 10 x 1:00 on, 1:00 off on steep board. I do this on the moon board and it's pretty darn hard by the end. Then do some core work after. As one gets stronger, I think there'd be a benefit to reducing the number of repeats but increasing the time "on" while holding the rest to 1:00.
Also, the HIT strip protocol from Horst takes about 45 minutes all the way through, and is really good power-endurance.