The take-home message is that researchers found that higher intensity (read: effort) yet short duration exercise bouts conferred equal endurance benefits as exercising at a lower intensity nearly 50 times longer. In other words, by working your tail off for a few minutes, you’d receive the same physiological benefit as someone who spent 5000% more time at the gym but merely plodded along.
That, I’d say, is significant. Work hard, kiddies.
With regards to the ab story, all I have to say is:
1. Most of Dr. McGill’s research (neat as it is) was done on spines from human cadavers. Cadaverous tissue, being dead, doesn’t respond the same way as tissue in a live (read: warm) human body - it is much less elastic and pliable. So much of the high force data McGill obtained is tainted by the inherent rigidity of cadaverous tissue (since you’ll register higher forces on a more rigid object).
2. Those who advocated “sucking in the abs” as opposed to “bracing” confused contraction with stability. In the same vein, tightening your shoulder muscles doesn’t mean “pull your shoulders up to your ears.”
3. Unless you’ve got a specific spinal problem you’re working on (with a qualified professional, I hope), you’ll be well served by working the basic exercises with a heavy (for you) weight. Performing multi-joint exercises that require abdominal stability will adequately work your core. Am I saying don’t do side bridges or bird dogs? No. But what I am saying is if you’re crunched for time, get your squats in first.