With planks, I always opt for RKC variations. You want to contract your core muscles (the muscles in your torso that are around your spine, not just your ‘’abs’’) as hard as you can, and you also want to contract your glutes, lats, and muscles in your legs.
One trick that is a total game-changer, and that will dramatically increase the difficulty and effectiveness of your plank, is to pretend that you are trying to pull your elbows down towards your feet. Even though your elbows/forearms do not move, the second I have clients do this, I can see the ‘’aha moment’’ that has just occurred. Pretending to drive the elbows down towards the feet reinforces the ever-important rib positioning, increases the effectiveness of the bracing, and dramatically increases the difficulty of the exercise. You should also do this during side planks, but of course you will only be ‘’pulling’’ one elbow/forearm towards your feet.
If you are performing a plank from your hands and feet, do the same thing, and imagine that you are trying to pull your hands down towards your feet. But for most people, planking from the forearms and feet is a better option, and makes using this trick a lot easier.
The next time you perform any plank variation, and you feel like it’s ‘’too easy,’’ and that you can ‘’hold forever,’’ ask yourself whether you are doing everything I described above, or if you are just mindlessly holding.
I often like to use planks as part of a warm-up, as they help prepare the body for the tasks at hand, and they help reinforce the lumbo-pelvic stability that is imperative in virtually all exercises you will need to perform.