Today, I’m doing a scaled version of the CrossFit workout called "Michael". You can look up the full variation. I often do variations of this since it is such a good fundamental workout for core muscle groups. And none of the muscle groups really interfere with other work that I do.

Here is the version I’m doing today.

4 Rounds for time:
Run 400-300-200-100m (begin each round with each)
40-30-20-10 reps of–
hyperextensions (or GHD extensions)
sit-ups (regular or GHD)