Before we dive into the top 3 crummiest ab exercises, let me just mention that very rarely is an exercise inherently risky, dangerous or ineffective.
Rather, the exercise just isn't suitable for the individual or they never learned how to perform the move properly (or train their abs properly, for that matter).
Furthermore, we've been thrown into a world of chairs and computers and tablets and phones and TVs, and our body is just struggling to survive. It wants to thrive, to be able to help us move, breathe, bend, stabilize, and all the other incredible things the human body is capable of doing, but we haven't given it the chance yet. We live in a chronically slumped over position, head jutted forward, hips tight and wound up, neck & back aching.
So we think, "I've just got to do some core exercises to get my abs and back strong!"
First off, props to you for taking the initiative. However, in a digital age of information overload, a lot of "mainstream" advice can leave much to be desired in the realm of efficiently training the core.
Here are your three worst ab exercises you're probably doing (and how to get an upgrade):
#1. Mountain Climbers.
Admittedly, I'm guilty of doing some really crummy mountain climbers in my past. Typically, these are done quickly, explosively, and with a ton of crazy hip sway all over the place. We collapse into our shoulders, we aggressively bend our hips into flexion as we drive our knee to our chest, and our pelvis just waddles all over the place trying to stabilize us. All sorts of nope going on here.
Instead, you have some "pre-reqs" you need to meet before wildly thrusting your knees to your armpits. First, do you have the shoulder stability to hold yourself in a locked push-up position? If not, start there.
Second, core stability is meant for, well, STABILITY. If you're aggressively bending your knees to your elbows (hip flexion), typically we'll get some lumbar (low back) flexion going on as well. Remember that one of the main roles of the core is to STABILIZE while other limbs are in motion. If our spine is flexing and bending, then we're not actually stabilizing the spine. We're just flexing it.
Here's a pretty mountain climber, slow and controlled. Much harder, right?
You knew this one was going to be on the list, didn't you? Sit-ups have gotten a ton of negative flack lately, and for mostly good reasons. However, remember that exercises are (typically) not inherently dangerous or inefficient, they just aren't best for that person.
With that said, sometimes sit-ups can be warranted, and I've certainly used them successfully with a minority of my physical therapy patients. But for the majority of human beings walking around in a slumped over position, sit-ups just exacerbate a rounded (flexed) position that we all reside in.
If you're already rounded over, why do more of it?
Surprisingly, this one makes the list. Planks are certainly not the worst of the worst, but I put them on here because they're wildly popular, yet they could be much better (and we like efficiency here, right?)
Most people will brag they can do a five minute plank or more, but that begs the question, how is the QUALITY of those five minutes?
Again, most people lack the shoulder stability to even stay that long in a plank with good form. Collapsing into the shoulders is very common with longer planks. Focus on pushing away from the floor in any push-up or forearm position, instead of drooping down.
Second, we often end up sacrificing form by hanging out on our back muscles and ligaments, without getting the strong, tight tension in the glutes and core in order to really maximize the exercise.
If you want to do a plank that's crazy effective, you shouldn't be able to hold it for longer than 15-20 seconds. Prioritize your quality over quantity. Squeeze your glutes, create a strong "shelf" with your shoulders, and imagine narrowing the gap between your elbows and toes to help activate your lats, quads, and anterior core. Oh, and then breathe.
You've made it this far, which to me means you are pretty damn committed to learning how to really maximize your core strength and generally be a more resilient, awesome human being, am I right?
If this is you, I've got good news.
If you want to really challenge your core stability, give me only three minutes of your day, for five days, and we'll see if we can really up the ante of your current routine. Even better: it's completely free, and only involves you and a floor.
Now let me warn you, this isn't going to be like any other core challenge you've taken before. This is a challenge that prioritizes quality over quantity. Nor is this about getting "six pack abs" in 5 days (and if anybody promises you that, they're full of BS). This is about improving your posture, building a strong and stable spine, reducing your risk of low back pain, and subsequently kick more ass in the gym and in life. Sounds pretty great, right?