Here is a term that is grossly overused in the fitness industry; 'core training." In most peoples opinions, this usually revolves around some sort of abdominal exercise such as sit-ups or crunches. Great, you can do all the sit-ups and crunches you want, that still may not lead you to have a strong core. What you fail to realize that your "core" is made up of muscles from the shoulders down to the knees and in a 360 degree rotation. So not only are the abdominals core muscles, but it ranges to all the muscles in the back, especially the "lats," the hips, and pelvis.
As many of my clients know, I rarely do any spinal flexion exercises like sit-up or crunches, because its more important for the lumbar spine to have stability and not mobility. Now in certain situations, there will be exercises that involve some spinal flexion, but in my sessions, I think training for stability is more important. Spinal flexion is, and has been a highly debated topic among trainers and everyone has an opinion about it one way or another, but this post isn't here to debate that issue. I'm here to discuss core training and what it really means, and maybe give some great tips to improve your "core" strength.
The best core exercises are the ones in which you are required to stabilize your body, with the most common example being a plank. In a standard plank you are hovering over the ground with your elbows and feet as the two points of contact with the ground. The elbows are also directly under the shoulders and hands are shoulder width apart(this will keep your lats engaged throughout the exercise). From this position, you are contracting the quads and glutes as hard as you can to keep the back stable and flat. This will work the entire core, all the way around and specifically the transversus abdominus(TVA) or the "corset muscle."
When this exercise gets to easy its time to add some instability or movement to increase its "functionality" You want to be able to teach your core muscles to fire through movement, this way when you pick up a box from the floor, the muscles instinctively fire to protect your back. For example, holding that same plank but alternating lifting a leg and/or an arm, or even walking laterally on the forearms and toes.
As for the posterior part of the body, exercises like a superman, in which you lay on your stomach and lift the arms and legs, help strengthen the back extensors and glutes(posterior chain). Simply changing the distance in which you extend your arms can greatly increase or decrease the intensity of the exercise. The further the arms are out, the harder and the closer they are to the body, the easier the exercise is. This is a simple physics 101 concept of lever arms. Another great way to strengthen the glutes(which are most definitely part of the core) is by doing hip bridges. In this exercise you keep the knees bent, feet on the ground, engage the glutes by contracting them(which will pull you into a pelvic tilt) and then lifting the hips off the ground. This has become a great exercise to help strengthen the lower back as well. Strong glutes = strong back. Add in a stability or medicine ball for an even greater challenge.
Another great way to stabilize is doing an exercise called an Anti-Rotation with an exercise band. Basically you have a band attached to a steady base like a pole and you hold the opposite end out in front of you perpendicular to the pole. You are trying to engage the same musculature as the plank, but you are also firing the hip stabilizers and the obliques. In my experience with my clients, this exercise ALWAYS appears too easy and too simple to be effective, but as soon as they are in position, the immediate reaction is "oh crap this is way harder than I thought."
Now take this stabilizing exercise and just like the plank, we'll add movement to it. So one big example that trips people up is simple lateral walks while keeps the hands in front of the chest. It requires a great deal of core strength along with some coordination and balance.
Which brings me to my final point about core training. When you properly engage and strengthen your core through the right exercises, your balance will improve tremendously. This is because all the little stabilizing muscles throughout the hip and trunk are strong enough to support balancing on one leg or even as simple as firing and activating correctly when you walk. In our specific training, we use ViPR's to relearn how to move again in all planes of motion or do exercises with a single leg which requires a lot of stabilization through the hip and ankle. A great example of a balance/core exercise is taken from yoga in the form of bird-dog. In this pose, you start in a quadruped position(hands and knees) and lift one arm and the opposite leg making sure the abdominals and glutes are engaged and that the back is in a neutral spine. I try to make my clients hold this pose for at least 20 seconds if not longer. Once you're comfortable with the balance on this pose, we can add a lot of other things like some sort of movement as with the anti-rotation and the plank. For instance bringing one's elbow and knee together will add a greater challenge than the standard pose.
Now these are just the basics for core exercises. When you train correctly, your core should be engaged on everything you do. This is where we bring in certain tools to force the body to compensate and engage to stabilize the body. So using a ViPR and doing a lunge with a shift or a chop will force the body to compensate in a certain way. This is something we try to emphasize through training.
In summary, the term "core training" has totally missed the mark in recent years. Even group "core" exercise classes have popped up and its nothing but crunches, crunches and more crunches. Crunches in every variation. Legs up, legs down, one leg, legs crossed, knees to the side. How many different types of crunches can one person do before they get bored or wake up one day and see that their body hasn't gotten any different or that their core hasn't gotten any stronger. Or even worse, they wake up with a back injury because of their constant crunching. I think its also partly the fault of all the information out there in magazines and on the internet. As a trainer I try to take the responsibility to educate my clients that there is more to the core than just abdominal exercises like crunches/sit-ups.