Planks: effective, challenging, and easy...in theory.
Whether you're just starting to add planks into your fitness routine, or have been doing them for years, I bet that you can agree that within your routine you reach a point when you feel like you may die (figuratively of course), but wish that you could hold on a little longer.
Luckily there are ways to push yourself to hold that plank even longer than before:
I have to remember tip #2 (I'm notorious for looking at the stopwatch). I hope this will help you get one step closer to your goals.