SPINAL STABILISATION

higher levels of co-contraction. The endurance objectives of a spinal stabilisation programme can still be achieved by increasing repeti- tions of the exercise in line with functional demands.

The success of endurance-based exercises to enhance spinal stabil- ity lies in being able to provide significant challenges to the back muscles, abdominals and abdominal wall without high lumbar compressive loading. To achieve this objective, early stage exercis- es should focus on placing the spine in horizontal positions, using no more than 10-30% maximum voluntary co-contraction of the abdominal wall and/or back extensors (see abdominal bracing tech- nique below). Later stages of progression may include performance- based or activity specific exercises using higher levels of muscle co-contraction, if deemed necessary.

EXERCISE PRESCRIPTION The following exercises have been chosen based on knowledge of tissue loading and functional anatomy of

the lumbar torso.

Evidently, many muscles function to stabilise the spine and protect the low back from injury, and as such, no single abdominal or back exercise challenges all the muscles involved in stabilisation, while sparing the spine (10). For this reason, the exercises given here are centred around approaches that promote stabilisation in the sagit- tal, frontal and transverse planes through correct coactivation pat- terns of the abdominal and back extensor muscles.

Endurance training of the abdominals The rectus abdominis and the muscles of the abdominal wall are all involved in creating spine stiffness, with the rectus playing a partic- ularly significant role via the generation of intra-abdominal pressure (11). The role of the obliques in lumbar stabilisation during upright stance (12), suggests that endurance training of the obliques can help maintain spine stiffness under gravity and external loads. Additionally, elevation of intra-abdominal pressure combined with co-contraction of the transversus abdominus and obliques undoubt- edly enhances stability (13), further supporting the use of ‘abdomi- nal bracing’ techniques in spinal stabilisation programmes.

Abdominal bracing The isometric abdominal brace coactivates all three layers of the abdominal wall and is much more effective than abdominal hollow- ing at enhancing spine stability (14). This technique is an impor- tant prerequisite for other stabilisation exercises. Once mastered, the abdominal brace can be integrated into exercises that train the anterior abdominal musculature (rectus abdominis) and the lateral musculature (transversus abdominis, lateral obliques and quadratus lumborum).

The abdominal brace is taught by instructing the patient to contract the abdominal muscles, as if about to be struck in the stomach. It is important to note that during bracing, the abdominal wall is neither hollowed nor pushed out. The bracing technique may be progressed by teaching patients to grade the abdominal co- contraction, for example 5%, 10%, 20% etc, of maximum voluntary contraction (MVC), as well as teaching how to maintain a brace during functional tasks. From a performance perspective, high levels of co-contraction are rarely required, even during strenuous activities (no more than 20-30% maximum voluntary co-contrac- tion), with stabilisation demands being addressed through muscu- lar endurance. For this to occur, the abdominal wall can be trained

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by having the patient perform an intermittent low intensity brace for up to 30 seconds, as well as activating a brace during other sta- bilisation exercises. The modified curl up is a performance-enhancement exercise that

Modified curl up (Figs.1a-b)

Figure 1a: Starting position

Figure 1b: Modified curl up

provides significant challenges to the rectus abdominis, and is inex- pensive in terms of lumbar compression. The patient is lying supine with one leg straight and one leg bent with the knee flexed, and spine in neutral (Fig.1a). The fingers are rested lightly on the fore- head. The intention of this exercise is to activate the rectus via rotation of

the thoracic spine, without producing significant

amounts of lumbar spine motion. During the exercise, the tongue may be placed in the roof of the mouth behind the front teeth to encourage stabilising recruitment of the neck muscles. The patient is instructed to brace the abdominals and elevate the head and shoulders a short distance off the floor stopping when the lumbar spine begins to flatten (Fig.1b). The focus of movement should be placed on thoracic motion without flexing the cervical spine, so that the trunk curls up against a brace. The end position is held for up to 10 seconds during which time the patient performs deep breathing, before returning and repeating for a total time of two minutes. As this exercise presents a significantly higher endurance challenge for the abdominal wall, it may not be suitable for decon- ditioned patients and may need to be modified by having the arms positioned by the side.

The abdominal bridge (Figs.2a-d) The abdominal bridge (and its variations) is a highly demanding exercise that ensures constant activation of the transversus abdo- minis, lateral obliques and quadratus lumborum, with minimal spine loads. When performed with bracing techniques and a neutral spine, it is almost impossible for the spine to become unstable.

The patient begins in a side lying position with the legs straight, and the upper foot/leg in front of the lower foot/leg (Fig.2a). The

Figure 2a

Figure 2b

Figure 2c

Figure 2d 15