Core Training Part 1: Sit-ups and Crunches?
Sunday, February 16, 2014 *from archives

By Kevin Hirose – BKin, CSCS

Since the beginning of time, or it seems, the sit-up has been a staple of core exercise for people trying to get ripped “abs” or wanting to build a strong core.  If one went to a gym a decade or more ago you would probably find that the only core exercise that was done back then.  But in recent years exercise and “back” experts have been proclaiming that sit-ups and abdominal crunches are bad for your back and that there are better exercises to strengthen the core such as the front plank, which is a core stabilization exercise. Core stabilization training has become popular lately and sit-ups do not dominate the gym scene as much as before.  But is it true?  Are sit-ups bad for your back and is core stabilization training superior and better for your back?  Let’s dig a bit deeper.

First of all – What is the core?  The core and the abdominals are not synonymous.  The “abs” that we see on TV and in magazines are only one set of muscles that make up the core – the rectus abdominis.  There is also theobliques, transverse abdominis, multifidus, erector spinae, pelvic floor muscles and diaphragm.  So how do you work all these muscles?  The answer is that they work together in various ways and degrees to move but more importantly stabilize the spine.

In my experiences as a personal trainer and strength coach I have found that many clients and athletes can go about doing sit-ups and crunches without causing any lower back pain, at least in the short-term. But on the other hand, those with existing lower back issues will very likely aggravate and/or worsen their condition. There are also studies which support the position that sit-ups can damage the spine if done repeatedly.  Here is a statement from Maclean’s Magazine featuring Dr. Stuart McGill, world-renowned Back Performance Specialist (from Canada!), regarding the sit-up:

“While there are lots of ways to injure a back, the sit-up is an easily preventable one. According to his research, a crunch or traditional sit-up generates at least 3,350 newtons (the equivalent of 340 kg) of compressive force on the spine. The U.S. National Institute for Occupational Safety and Health states that anything above 3,300 newtons is unsafe.”

If you look at how the human body moves, in general, it does not move in a sit-up or crunch-like motion very often except if you are doing those exercises. However, the core does function in daily life and sports to support or “stabilize” the spine in order for the body to move as a unit.  Based on this concept alone asks the question, “how would sit-ups help the core stabilize better?”.  Well, in simple terms, they don’t. The abdominals may become stronger in the flexing (crunching) motion but will NOT become stronger during stabilization therefore one would have to do core/spine stabilization exercises to achieve this.

It is also very important to note that this philosophical shift in core training has been prevalent in the realm of Strength & Conditioning for several years and continues to evolve and to be the foundation of most skilled practitioners and programs . The excerpt below is evidence of change that has occurred in the testing and training of US Soldiers and First Responders such as firefighters, in which physical fitness is vital.

“A study of U.S. soldiers published earlier this year in Medicine & Science in Sports & Exercise compared sit-ups with back-friendly core stabilization exercises, including bird dogs, and found there was no difference in overall fitness between the two groups. In fact, those who did core exercises showed significant improvement in the army’s sit-up test.” -MACLEAN’S 2010

Okay, sounds simple enough; do core stabilization exercises. Well, which ones should are effective and what in the heck is a “bird dog”?

Let’s begin by examining the front plank.  As simple as it sounds the vast majority of gym-goers do it incorrectly.  Firstly, they often hold the incorrect position meaning that they are doing one or more of the following:

–excessive lumbar extension (lower back sagging)
–excessive kyphosis (upper back rounding)
–asymmetry (tilting and/or general unevenness)
–head poking forward OR cervical extension (looking up away from floor)
–knees bent
–lack of tension and stability

And most plankers almost always lack muscular tension and therefore lack stability during any plank variation.  In my opinion, it is those same exercisers who believe that holding a plank for time is the goal.  Yes, holding a plank for a minute is not that hard for many people but try holding it with some tension and your ability to hold it for time dramatically decreases.

Unfortunately, the remainder of the core exercises will be listed and described in the next entry.  The reason for dividing this article into two parts this is to not overload you with information in one barrage and allow you time to absorb it before the next releasing the second part.

In conclusion, flexion core exercises such as the sit-up and crunch are NOT necessarily “bad” but they are higher risk in regards to spinal injury for particular individuals.  And in my opinion, core stabilization protocols are a safer and more functional way to train the core in both athletics and everyday life.  So it would be a good decision to introduce this type of exercise into your routine if you have not already and to ditch core flexion if you have lower back issues.  Please read the conclusion to this entry titled “Core Training Part 2 – A Deeper Look into Core Stability”.