Have you ever noticed how so many people doing crunches never get the abs they want?  Why is that?  There’s really a lot that determines how easy it is for your abs to be defined, everything from genetics to proper nutrition, but there’s one thing that a lot of people don’t think of.  It’s called optimal length-tension relationship. 

Length-tension relationship deals with the force a muscle can produce at a certain length.  Try this exercise.  Bring your right knee to your chest and try to squeeze your right butt check.  What happens?  You can’t.  Now try this.  After bringing your knee to your chest and squeezing, straighten that same leg out so that you’re back to standing on both feet.  Try and squeeze the right side again.  Now you’re able to tighten the muscle just fine.  Why is that?  It’s because when you bring your right knee to your chest, your right butt muscle is stretched out.  When you bring your foot back down to the ground, the muscle is shortened again, meaning it’s at a better length to provide force and squeeze.

This same principle applies to all the muscles throughout your body, so when looking at the abs, there’s an optimal length that will allow your abdominal muscles to contract or tighten properly, giving you the “six-pack” definition you want.  Now keep in mind, as I said earlier, there are multiple factors that determine abdominal definition; this is just one of those factors.

So how do you know if your abs are at the optimal length to provide the right amount of tension during your ab workouts?  Remember, the right amount of tension in your workouts will lead to the muscles developing faster and becoming more defined.
 
There are a few muscles that can contribute to a length-tension problem in your abs.  The two most common are your low back muscles and your hip flexors.  To make this a little simpler, I want to look at the core area.  Your abdominal muscles, hip flexors, and low back muscle all connect relatively in the same area.  The hip flexors and abs connect to the front of your pelvis, and the low back muscles connect to the back of your pelvis.  If your hip flexors or low back muscles are extra tight, your whole pelvis can shift forward, causing a lot of posture problems.  For example, a person with their pelvis tilted forward walks with their butt sticking out, and a person with their pelvis tilted back walks as if they’re sore from riding a horse.

If you sit down, squeeze your groin area, and lift your leg off the chair; you’ll feel your hip flexors.  Like I said, they run from your spine and the front of your pelvis to your leg, and when tight, they tilt the pelvis forward.  The low back muscles, if you remember, connect to the back of the pelvis, and when tight, they also tilt the pelvis forward.  So what does this have to do with a six-pack?  As you know, the abs also connect to the pelvis, so if the pelvis is tilted forward, the abs are stretched out too much.  This means they aren’t at an optimal length to contract.

Going back to the knee to chest example, a lengthened butt muscle means the butt can’t be squeezed together properly, just as lengthened abs can’t.  This means when doing abdominal exercises, if you have a tight low back or hip flexors, your abs won’t have enough tension in them to properly develop.  A great indicator of tight hip flexors or a low back is when you do crunches, do you feel it in your hip flexors or low back?  If you do, then that means your abs aren’t strong enough to handle the work, so they’re calling on these other muscles to assist.  If these other muscles are doing most of the work, then they’re being overworked, and this’ll lead to tight hip flexors and low back muscles. 

If you have this problem, my suggestion is to ease up on the amount of abdominal exercises you’re doing.  Three sets of 15-20 reps is plenty for an abdominal exercise; anything over that can lead to overtraining your abs, which in turn can lead to a tight low back and hip flexors.  Another thing to do is stretch and foam roll your low back and hip flexors.  Here's how you do that.  By doing all this, you can help prevent your posture from being out of whack, and your abs will be at a better length to develop properly.

Like I said at the start, this concept applies to all muscles.  If you want to develop your chest more, make sure your upper back and shoulders aren’t too weak.  A weak upper back and shoulder area leads to slouching (common with people who are always bent over a desk), and slouching leads to the shoulders being drawn in and the chest becoming too tight.  If the chest is too tight, you won’t be able to develop it properly. 

So like I said, this applies to all areas of the body.  Whatever muscle group you’re trying to improve, stop and think before you continue working on it.  Make sure that your posture supports the development of it.  If not, then correct it.  As you’ve probably figured out, this can be very complicated; that’s why it’s not a bad idea to consult with a personal trainer or other fitness professional.  Hopefully though, you can apply these simple tips and have better success with your fitness program as a result.

Dan Falkenberg, BA, ACE-CPT, NASM-PES 

Dan can be reached at DanFalkenberg.com.