There has been lots of debate about what type of stability method should be used when controlling muscle activity in the torso. There was a large overreaction when Hodges and Richardson (1) came out with research showing the importance of the transverse abdominus in lumbar spine stability. People quickly jumped on this one, implementing all the TA and draw-in training we could handle. Problem was that the study related to people who already had back pain and there was a delayed firing of the transverse abdominus, which is actually one of the first muscles to activate upon movement in healthy individuals.
A few years later Stuart McGill, one of the top back specialists in the world, came out and said that drawing is not the best way to stabilize the spine; we need to "brace" the core. Now we fall along the line that we just need to stabilize the lumbar spine, while training the correct movement patterns of the hips, thoracic spine, and scapula.
Now we come back full circle again as a recent study (2) shows that the abdominal draw-in method is an effective method to reduce anterior pelvic tilt and help disassociate erector spinae activity from the glutes and hamstrings during prone position hip extension.
The problem I see is, we jump on a band wagon of a new and supposedly innovative idea and forget all the other effective methods there are at getting the job done. As many in the field have said before, there is always an immediate overreaction in the first few years of a new concept, then an under-reaction, and finally reaching a happy medium some years later.
With the activity of the torso, I believe, different tasks require different methods of stabilization. If somebody has low back pain, it may be warranted that they need to work on activation of their transverse abdominus as the Hodges and Richardson research showed. For maximal effort back squats, I would argue that we need to adhere to McGill's advice and "brace like hell". When lifting something directly overhead, such as a stand dumbbell press, we need to draw-in a little and activate our obliques to avoid hyperextension of the spine. Or, if your somebody like me who has tight hip flexors and an anterior pelvic tilt, the draw-in method is of high importance in limiting the use of the lumbar erectors and allowing for true hip extension.
Regardless of draw-in or brace, we just need to find the optimal method for the specific task and individual.
1. Hodges PW, Richardson CA. Inefficient muscular stabilization of the lumbar spine associated with low back pain. A motor control evaluation of transversus abdominis. Spine Journal 1996 Nov 15;21(22):2640-50
2. Oh JS, Cynn HS, Won JH, Kwon OY, Yi CH (2007) Effects of performing an abdominal drawing-in maneuver during prone hip extension exercises on hip and back extensor muscle activity and amount of anterior pelvic tilt. The Journal of Orthopaedic and Sports Physical Therapy 2007 Jun;37(6):320-4