1) Abdominal crunches and leg raises.

Everyone is obsessed with abdominals and, as a result, most people end up over working them; and worse, working them improperly. Over-working your crunches simply adds to a flexion-chain imbalance, pulling your hip forward and your ribcage down...making you look "slumped" and exposing you to a flat back syndrome and back pain.

Lying leg raises are a big offender and the hanging leg raises produce so much force through the sacroiliac joint and lower lumbar that it is very dangerous for the average person.

Here is a test you can do if you are currently doing leg lifts. Lie flat on your back and slide your fingers under your lower back on each side. Now, slowly apply pressure to your fingers by flexing your abs. Not too much pressure, just enough so that you can tell that your abs are activated. Now, keeping equal pressure, try lifting just one let straight up and slowly back down without losing any pressure or "squishing" your fingers. If you cannot pass this lower ab strength test, what do you suppose is working when you have been doing your leg raises? Not your lower abs since they cannot even stabilize one leg properly. This results in compensation throughout the kinetic chain and a LOT of activation of the lower back just to stabilize the discs. In other words...murder on your back.

2) Running:

This will be a not-so-welcome addition for many of my avid runners. However, In my experience, I find that running poses a threat to the back in two ways:

First, people who are just looking to get into shape very often default to running to "lose that extra weight." The major issue here is that when you run, you multiply the shock of each step by several times that of simply walking. For a deconditioned person, this means that the ligaments and tendons are too weak to handle the load, particularly if the individual is already carrying around extra weight. This can lead to major joint dysfunction in the knees, hips, and sacroiliac joint, causing the muscles around these joints to spasm and cause pain.

Second, my avid runners often develop huge muscle strength imbalances due to the constant repetition of running. Chronically tight hamstrings, caused by a lack of glute function, will pull the pelvis down and cause a flat back resulting in lumbar pain. I call these people my "no butt" clients because they have a flat back tight, chest, and slumped shoulders giving them the appearance of slouching and flat bottoms. Unfortunately, this posture is also reinforced by sitting in a chair all day at work and eventually the lower back loses too much curve, the spine can no longer distribute the force of running efficiently, and we get pain as muscles spasm.

3) Seated Leg Press or Sled Press.

My guys are notorious for piling a ton of weight on this machine to impress their friends. Unfortunately, most of them do not have the flexibility to actually do the proper movement through the entire range and end up recruiting their lower back to move all of that weight.

Simply put, if you are lying against the pad, your lower back should NEVER come off of the mat. If you can not bring the sled down far enough to complete the range of motion, you need to stretch you hams, glutes, and calves or switch to a more functional (and in my opinion more beneficial) standing squat as long as your form is good.

Imagine your glutes being very tight and your lower back curling off of the mat on the way down. What muscles do you suppose have to activate in order for you to push the sled back up? Yes, your lower back erectors. This is a great way to slip a disc or traumatize your lower back muscles.

This list is not an "AVOID AT ALL COSTS" list. I do, however recommend that you avoid these exercises until you have any postural problems cared for by a corrective exercise coach or physical therapist. If you have a healthy back, and are currently doing these activities, make sure that you are doing them properly so you maintain your healthy back. You can watch for signs of chronic tightness (stiffness that will not stretch out over time) as a good indicator that something in your exercise routine is causing a muscle imbalance. Make sure that you go to a professional who is trained to assess and correct these imbalances and give you a new exercise routine which will keep