By Leith Darkin
March 2002

 
I'm sure you've heard the saying that "a chain is only as strong as the weakest link", well this saying is very true as far as the human body goes. Most recreational gym patrons and amateur sportsman and sportswomen tend to spend allot of time conditioning the upper and lower body but tend to neglect the core area as far as quality or specific training goes.
 
The main support system for our trunk is transversus abdominus which works in conjunction with our diaphram, pelvic floor and multifidus (deep erector spinae muscle).
Tansversus abdominus wraps around our trunk, attaching either side of our spinal column with the upper portion attaching to the ribs and the lower portion attaching to the pelvis. The main function of transversus abdominus is to act like a corset when it is contracted.

As transversus abdominus contracts, it pushes our intestines and internal organs in an upward direction against our diaphram and in a downward direction against our pelvic floor muscles which in turn increases our inter abdominal pressure (our core area is now acting like an air shock absorber). The strength of transversus abdominus is relative to the amount of pressure we can build up in our core area, the more strength the more pressure and just like our car shock absorber, the more air we pump into it, the more weight we can have in the back of the car or trailer.
 
In the gym environment you'll find that the common way to specifically train transversus abdominus is with the use of fit balls (swiss balls), now for the recreational gym user whose goal is fitness, health and some muscle tone, the use of a fit ball is probably adequate. For the individuals that attend a gym for rehabilitation purposes (especially back injuries) the fit ball can be a great tool.

For the individuals who are serious about their sport, more specific and functional exercises are more appropriate. The main disadvantage with fit balls is they are non-specific to every day activities and sporting movements, if you train on a fit ball you get good at "training on a fit ball". If your core work is done on a fit ball in a seated position, prone (facing down) or supine (facing up) then the way you are training transversus abdominus isn't going to be as effective as training transversus abdominus with your body standing in an upright position resisting gravity. Often fit balls are used to sit on while performing single arm dumbbell exercises, the idea behind this being that as the arm moves away from the bodies center of gravity, transversus abdominus has to contract to stop you from falling off the ball, while this is true, you can get the same effect standing on one leg.

When standing on one leg, not only are you addressing core stability by standing upright resisting gravity, you are also addressing ankle, knee and hip stability as well as pelvic control and body alignment.

As humans we evolved as upright beings, in the upright position we have the force of gravity bearing down upon us, in fact our whole evolutionary process has evolved around gravity. Our bones are our bodies main support structure which enables us to stand upright, resisting the force of gravity. Our muscles are designed to help us move around freely in the presence of gravity. Our heart is designed to pump blood in an upward direction to the brain resisting gravity and the veins in our legs have one way valves which are designed to open when our leg muscles contract then close to stop the blood flowing downwards in the direction of gravity. Even the way in which we consume food and pass waste products is dependent on gravity
 
To work transversus abdominus effectively we need to be in the upright position so it can do what it was designed to do, to support our trunk while resisting the force of gravity when lifting, to stabilize the body when running, jumping, climbing, throwing and striking. Amazingly we can squat more than two - three times our body weight, but to do this as well as strong legs we need that strong core area

What are the more effective ways to train the core area?
 
Athletes indirectly train their core area through their specific sporting movements. When applying one of our more important training principles "specificity", you cant get a better training stimulus for a particular sport than the actual sporting movement itself. Athletes that have the greatest core strength are those that participate in Olympic lifting (clean and jerk & power snatch) and your power lifters. The desired outcome of these lifts (with the exception of bench press) is to lift a resistance against gravity while the body is in the upright position. It's through years of repetitious practice that builds a strong core specific to these lifts. With kickboxing it's the continual kicking and punching to bags and pads, which increases the strength of the core area specific to that movement. With the round kick, Its rectus abdominis and the obliques (with a small contribution from the erector spinae muscles) that contribute to the dynamic movement of the trunk and transversus abdominus that holds body positioning through the movement of the kick and stops the body from folding on impact.
In addition to the continual practice of sporting movements, resistance training can be of great benefit. You'll find that all professional athletes participate in resistance training to help them excel in their chosen sport and allot of amateur athletes who take their sport seriously are also involved in resistance training. As far as training transversus abdominus goes, you cant beat your big lifts, as they train transversus abdominus in the manner in which it was designed to work (stabilizing the body in an upright position, resisting the force of gravity). These lifts include BB back squat, BB front squat, free weight lunges, dead lifts, power cleans and hang cleans. When looking at dynamic movements, in addition to transversus abdominus you need to train the trunk flexors, extensors and rotators.
 
Rectus abdominis
 
So far research has shown that rectus abdominis (our six pack) is a trunk flexor and lateral trunk flexor. If we are lying on the ground supine (face up) with our knees bent at 90 degrees and our feet in constant contact with the ground, when our upper body moves we have trunk flexion or what's commonly known as a curl up or abdominal curl. If our upper body remains on the ground and we bring our knees to our chest we have a reverse curl (with some additional help from our hip flexors). You'll find most training for rectus abdominis whether done on a fit ball, on a sit up bench, in a machine or on a hip flexor stand are all variations of the curl up or reverse curl.
 
Lower body remains stationary
while lower body moves
Upper body remains stationary
while upper body moves

Does rectus abdominis assist with core stability?
 
In theory no, every anatomy book and article I've researched suggests that rectus abdominis is a trunk flexor and trunk lateral flexor only, however from my personal experience of lifting weights and from testing individuals whose training I've been involved in, it would appear that rectus abdominis does contribute to core stability but only under more extreme conditions. I tested two individuals on a squat and deadlift.

The resistance lifted was a 12 RM, 6RM and a 3RM with 3 minutes rest between sets (RM is repetition maximum
E.g. a 6RM is a weight that can only be lifted six times).

While the individuals attempted their 12RM, 6RM and 3RM of the squat and deadlift I stood behind them and pressed my hands against their stomach to feel the contraction of rectus abdominis.
With the 12RM there was hardly noticeable change to the tension of rectus abdominis.
With the 6RM there was some contraction of rectus abdominis.
With the 3RM there was definitely a strong contraction of rectus abdominis.

The reasons for the isometric contraction of rectus abdominis under load I can only speculate. It's possible that because rectus abdominis covers a large portion of the anterior (front) section of transversus abdominus, under more extreme load rectus abdominis contracts to give transversus abdominus a firm base to contract against (similar to a weight lifting belt).

Another reason for this theory is the thickness of transversus abdominus varies as it wraps around the trunk, the thinness portion of transversus abdominus lies directly beneath rectus abdominis. It's also possible that under extreme load rectus abdominis contracts isometricly to press against transversus abdominus which in turn builds up even more internal pressure.
 
 
Effective ways to train rectus abdominis
 
When training rectus abdominis effectively it's important to address our technique to achieve our desired results. From my experience working in gyms over the years, people tend to train their "abs" differently to the rest of their body. Often the repetitions are done explosively in an uncontrolled manner with the end result being to achieve as many cheat reps as possible. If you don't train the rest of your body in this manner then why train your "abs" this way?
 
When training rectus abdominis (your six pack) I try to use a gauge where possible so the individual can measure their progress. With the "curl up" I get the individual to straiten their arms and fingers, and as they curl up they run their fingers up their legs trying to get as high as possible. Their gauge is either finger tips to the top of their knees, first joint to the top of the knees, second joint to the top of the knees, base of the fingers to the top of the knees, bass of the thumb to the top of the knees, wrist to the top of the knees or one inch past the wrist to the top of the knees. To ensure the individual doesn't cheat I get them to do a three to four second concentric contraction (as the individual curls up) with a two second pause at the top and a three to four second eccentric contraction (as the individual lowers them selves).
 
Once an individual has worked out high they can raise them selves, they must come up to the same height every contraction, if they cant its time to stop as they are too fatigued to maintain quality. While going through the repetitions, if the individual can't maintain a three to four second concentric and eccentric contraction with a two second pause in between the contractions then it is time to stop, as the individual is too fatigued to maintain quality. If the speed of movement varies during the three to four second concentric or eccentric contractions then it is time to stop, as the individual is too fatigued to maintain quality. If you achieve your chosen rep range without cheating then it is time to move onto your next gauge.
 
When attempting a reverse curl, our starting position is 90 degrees at the hip and knee joint and your gauge is to be able to touch your shoulders with your knees. Once again to ensure quality we are looking at a three to four second concentric contraction, a two second pause as you touch your shoulders with your knees and a three to four second eccentric contraction. The same rules for quality apply as for the curl up, if you cant touch your shoulders or maintain the quality of the contractions then it is time to stop. As the reverse curl is an advanced exercise if done properly, many individuals will find that they just don't have the strength to attempt this exercise, however with the use of gravity we can make some easier progressions.
 
When starting this exercise, instead of being 90 degrees at the hips and knees you can straighten your legs so that you are 90 degrees at the hips with your legs straight pointing upwards (180 degrees at the knee joint), as you bring your knees to your shoulders (with your legs straight) you will find that gravity is now assisting you by pulling your legs to the ground. Your progressions will be any angle from legs straight to a ninety degree bend at the knee joint.
 
 
The use of a decline sit up bench is also a good tool for training rectus abdominis, the advantage of this devise is that you can hold additional weight to your chest as your strength improves. Once again you are looking at a three to four second concentric and eccentric contraction with a two second pause at the top. If technique suffers then it is time to stop. You should also be aware that there is a strong contribution from your hip flexors in this exercise so I would suggest including a hip flexor stretch to your stretching routine if you don't already.
 
The use of fit balls is another good tool for training rectus abdominis, by changing your arm positions you can increase the length of your upper bodies lever which in turn gives you greater resistance against gravity. I encourage full range of motion, from sitting upright (90 degrees) to lying right back (180 degrees), this full range of motion gives us a gauge to work with for consistency. Once again we are looking at a three to four second concentric and eccentric contraction with a two second pause at the top, if technique suffers then it is time to stop.
 
Cable crunches and abdominal machines are other forms of resistance training for rectus abdominis, I would be encouraging a two to three second concentric and eccentric contraction with a one to two second pause in between. With the cable crunch from the kneeling position it is important that there is only movement from the waist upwards (no movement at the knee joint).
 
 
You'll find that most other exercises for rectus abdominis are variations of the above. The use of balls, sit up benches and machines are just tools for variety, which enables us to challenge rectus abdominis in different ways. The biomechanical principles for all these exercises revolve around the curl up (lower body remains stationary while the upper body moves) and the reverse curl (upper body remains stationary while the lower body moves).
 
In all the above exercises and other exercises targeting rectus abdominis, there is a large contribution from the internal oblique and the external obliques . In some exercises such as the reverse curl you'll find some involvement of your hip flexors (lower body movement while upper body remains stationary), while other exercises such as an incline sit up you will find a larger contribution from the hip flexors (feet are anchored under a fixed object). The use of the hip flexors when training rectus abdominis is fine so long as you maintain their flexibility. When sitting on a fit ball (unstable environment) there will be some involvement of transversus abdominus, however by doing a three to four second concentric and eccentric contraction with a two second pause between contractions on exercises where the lower body remains stationary and the upper body moves and gravity is providing the resistance, there will also be a contribution of transversus abdominus, as transversus abdominus has to contract to hold the body stable through out the contractions.
 
Effective ways to train obliques
 
Your obliques contribute to trunk flexion, so if you've been training rectus abdominis you've also been training your obliques. If you're after some additional training then there are some variations of lateral flexion with weighted resistance. From a standing position you can use dumbbells or low pulley cables. When training your obliques in this manner it's important to once again use slow and controlled movements with a two to three second concentric and eccentric contraction and a one to two second pause in between. With lateral flexion it is important to watch your range of motion, when going through extreme ranges of motion, (especially going through extreme ranges of motion in a ballistic manner) you run the risk of excess pressure on your discs.
 
 
A more advanced version of this exercise is lying on your side on a bench with your feet anchored, this exercise is more advanced and I wouldn't recommend it unless you have some training years behind you. Our obliques are also designed to rotate the trunk, however rotation can be dangerous to the spine and discs when done under load. If your sport has a rotation component in it (eg. a round kick) then some weight resistant rotation could be of benefit, but only under the guidance of a qualified trainer or coach.
 
Effective ways to train the erector spinae
 
When training your erector spinae, your more functional exercises are the squat and deadlift. These exercises train the erector spinae muscles to extend the trunk in an upright position resisting gravity. The deadlift replicates lifting technique that can be used in every day life and in some instances the sporting arena. A more common exercises that is less functional to every day life, but is also effective for training the back extensors is the back extension. The back extension can be done either on a fit ball or on a back extension frame. With the back extension we have to watch our range of motion, when extending the trunk we come up to a height where our ankles, hips and shoulders are in a straight line and not beyond. Slow controlled movements are once again important with this exercise, a three to four second concentric and eccentric contraction with a one to two second pause in between.
 
 
Conclusion
 
If your interest in martial arts is serious enough for you to be involved in resistance training, then it is important to address your bodies core and surrounding muscles with exercises and technique that is going to be effective in helping you achieve your goals.

When addressing transversus abdominus, its alright to incorporate some of your less functional exercises (fit ball, prone stabilizing, etc) for variety, however the majority of your training should revolve around exercises that train transversus abdominus in an upright position resisting gravity.

When training trunk flexors, extensors and rotators choose exercises that have effective progressions and a gauge to measure your repetitions and progress if no external load is involved.
Use appropriate technique with controlled repetitions and use rep ranges that are specific to your goals.
Where possible choose exercises that are specific to your needs and the needs of your sport.
 
Download this article in PDF format
231Kb
To view the above article as a PDF you need to instal ADOBE ACROBAT READER. This is a freely available plug-in/software available from ADOBE at www.adobe.com or simply click the logo to go there...