Yes, this is super weird. But it nails the transverse abdominis (the deep core muscle that's like a natural weight belt) and even the internal obliques.
The transverse abdominis is a deep core muscle that acts as a natural weight belt for your spine. It's the Spanx of your abs. Developing it will help prevent injuries and create a smaller waist. You could train it with plank variations, but I like this exercise using an ab wheel and a treadmill.
Hold the ab wheel the same way you would for a rollout, but instead of rolling out, you hold it like a plank. This will also hit the internal obliques. It's fun and quite possibly a better use of the treadmill than jogging for abs. The slower the treadmill goes, the harder it is.
Gary Homann isn't your garden variety weightlifter. Sure, he's 180 pounds at 6% body fat. Sure, he had the best 500 meter indoor rowing time in the world last year in his class and he's been an ACSM certified health and fitness instructor for the past nine years. But Gary's also got a Master's degree in applied health psychology and is currently working on finishing his Ph.D. in psychology.
A rep is not a rep. Especially when you stretch it out 30 times longer than how it's normally done. Sounds crazy, but so are the gains you'll get from it. Check it out.