Core Stability Training
As we have seen, the core stabilising system (CSS) involves the transverse abdominis (TA) and the multifidus muscles. By attempting to contract the TA, you also cause the multifidus to contract. This paired contraction provides for great stability to the lumbar area.
The action of the TA is to contract isometrically and tighten the abdominal area. In effect, it pulls the umbilical area backwards towards the spine. Many people, mistakenly, think they are contacting the TA when they "suck in" their abdominal area: this does not specifically activate the TA and is more likely to be a result of contraction of the external obliques. There are some techniques used to try and isolate the TA:
push the belly button out as in making a "pot belly" and then slowly try and reverse the movement
lie on your stomach or get on "all fours" and let your belly button area relax, and then try and lift it up
lie on your back with your hand under the arch of the back. Try and contract the TA area and make sure there is no change in the pressure on your hand
The key to activating the TA correctly is to try and squeeze it slowly and gently: if you try and contract the TA too hard or too quick, then you will probably be contracting the rectus abdominis or the obliques. When your are first learning to activate the TA in isolation, you need to practice contractions frequently - up to 6 sets of 10 contractions per day. You will need to do this for maybe a few weeks until you can activate the TA at will. The contractions should be isometric contractions at about 30% of maximum. You should hold the contractions for 10 seconds, and then rest for 10 seconds. Continue with this 10" hold 10" relax regime for the 10 contractions. It often helps to have a trained professional assist you to ensure that you are achieving a correct contraction of the TA.
Once you have gained good control over your TA, then it is time to strengthen them. A common way to do this is with the use of Swiss Balls. These can be hard to balance on, and by gently contracting your TA you can increase your stability on the ball. This challenges the TA and helps to strengthen them. These exercises can be progressed by trying to maintain balance whilst lifting one foot a little off the ground. Or, you can put one foot on a ball. It is all about challenging your stability, and using your core to maintain a stable posture.
Eventually though, the CSS must be used in a variety of realistic positions. The next step up is on surfaces such as wobble-boards and mini-tramps. Maintaining balance whilst being challenged more strongly is the key. Then the skills must be progressed into practical situations such as standing, walking, running, jumping, hopping and lifting.
In weight training, there are many instances where the CSS can be utilised, and should be utilised, to maintain good technique and to enhance performance. Using the CSS can mean a stronger base to work against, as the torso is a more solid base for the arms or legs. Good examples are when bench pressing, performing shoulder presses and when squatting.
It is commonly seen, when people are performing a bench press, that they arch their back when they start to fatigue or when struggling with a weight. Presumably, this changes the angle of attack on the pecs, so that different fibres are called into play. However, the position of the arched back, under load, can be stressful to the back and cause injury. If the back is able to arch like this, it suggests that the back is not a stable, rigid structure throughout the performance of the exercise. So how does this unstable platform affect performance? It would decrease the efficiency of the arms, and increase the use of the stabilising muscles. By ensuring that your trunk is rigid throughout the exercise, which requires only light to moderate activation of the CSS, you can increase the efficiency of the exercise and preserve your back. The same principle applies with doing shoulder presses where arching of the back is also commonly seen.
With squatting, there can be an immense load placed on the spine, in the form of a compression force. There can also be quite a flexion force on the spine if technique is wrong, or at the bottom of the squat if the lumbar spine is pulled into a flexed position. Use of the CSS can help prevent both of these problems. Firstly, recall that the CSS works partly by applying an extension force to the spine, countering flexion forces. Secondly, the CSS can act to take some of the compression forces off the discs. So, using the CSS can enhance the safety of the squat exercise. It is a much more effective mechanism than using a weight belt, as it can brace the whole lumbar spine, and not just one part. It can also serve to remove load off the spine, which weight belts cannot do. The CSS should be set at the start of the descent, and further activated on the ascent phase of the squat.