An abdominal brace occurs when you have contracted both the abdominal, lower back, and buttock muscles at the same time.
Here is how to perform the maneuver:
Stand up straight and place one hand on the small of your back and one hand on your abdomen.
Bend forward at the waist and feel the lower back (extensor) muscles contract.
Come back to an upright posture and feel them “turn off.”
Without bending forward, contract the abdominal muscles (like you are about to get punched in your gut – feel them tighten with one hand) and the buttock muscles (as if you are holding in a bowel movement). You will feel the lower back muscles contract (with the other hand) when you contract your abs and buttocks.
Another way to feel the brace is to try coughing or blowing out as if you were going to blow out a candle. You will feel the contraction in abs, low back, and buttocks.
Core stability training begins with learning to co-contract the TA and MF muscles effectively as this has been identified as key to the lumbar-support mechanism.
To perform the TA and MF co-contraction, you must perform the ‘abdominal hollowing’ technique with the spine in the neutral position. Use the following guidelines: Start by lying on your back with knees bent. Your lumbar spine should be neither arched up nor flattened against the floor, but aligned normally with a small gap between the floor and your back. This is the ‘neutral’ lumbar position you should learn to achieve. Breathe in deeply and relax all your stomach muscles. Breathe out and, as you do so, draw your lower abdomen inwards as if your belly button is going back towards the floor. Pilates teachers describe this as ‘zipping up’, as if you are fastening up a tight pair of jeans. Hold the contraction for 10 seconds and stay relaxed, allowing yourself to breathe in and out as you hold the tension in your lower stomach area. Repeat 5-10 times.
•It is absolutely vital that you perform this abdominal hollowing exercise correctly otherwise you will not recruit the TA and MF effectively. Bear in mind the following points:
Do not let the whole stomach tense up or your upper abdominals bulge outwards, as this means you have cheated by using the large rectus abdominus muscle (the six-pack) instead of TA.
Do not brace your TA muscle too hard; just a gentle contraction is enough. Remember it is endurance not max strength you are trying to improve.
Do not tilt your pelvis nor flatten your back, as this means you have lost the neutral position you are trying to learn to stabilise.
Do not hold your breath, as this means you are not relaxed. You must learn to breathe normally and maintain the co-contraction of TA and MF.
Use your fingers for biofeedback on either side of your lower abdomen to feel the tension in the TA muscle.
Once you have mastered abdominal hollowing lying on your back, practice it lying on your front, four-point kneeling, sitting and standing. In each position, get your lumbar spine into neutral before you perform the hollowing movement.
Thera-Band® exercise balls are used by therapists and trainers around the world for therapy and fitness training. Despite its widespread use, the exercise ball has lacked in research to support its clinical application. Some studies have shown that abdominal exercises performed on exercise balls produce more muscle activation than the same exercise performed on a stable surface (Vera Garcia et al. 2000). In addition to traditional abdominal crunches, the exercise ball offers a variety of exercises aimed at activating the core muscles. With the variety of exercises being performed on exercise balls, more research is needed to prove or disprove the efficacy of specific exercises.
Physical therapy researchers quantified the electromyographic (EMG) activity of the abdominals, latissimus dorsi, lower back, and quadriceps muscles during eight “core” exercises on the exercise ball in 18 healthy subjects. They reported their findings in the Journal of Orthopedic and Sports Physical Therapy.
They found that the upper and lower rectus abdominus muscle were most activated during the roll-out (63% and 53% of maximum, respectively), and pike exercises (47% and 55%), while the internal and external obliques were most active during the pike (84% and 56% respectively) and skier exercises (73% and 47%). Not surprisingly, the lumbar paravertebral muscles, latissimus dorsi, and rectus femoris only produced low- to-moderate activity (less than 40% maximal activation) in all exercises.
The authors concluded that the roll-out and pike exercises on a Thera-Band exercise ball were the most effective exercises in activating the abdominals while minimizing low back and rectus femoris activation. In addition, these exercises produced more activation of the core muscles than a traditional crunch or sit-up.
REFERENCE: Escamilla R et al. Core muscle activation during swiss ball and traditional abdominal exercises. J Orthop Sports Phys Ther. 2010 May;40(5):265-76.