GROIN INJURY PREVENTION external oblique muscle internal oblique muscle transversalis fascia

deep inguinal ring

liguinal ligament

conjoined tendon

Superficial inguinal ring

selective recruitment of transversus abdominus muscle takes place, the pressure on the air bag decreases and this is displayed on the dial for the benefit of the clinician and client (Figure 1). The pressure biofeedback unit is an excellent tool that helps to facilitate isolated transversus abdominus activation

O'Sullivan (11) described the progression from isolated activation of the local system in a non functional position, to dynamic pos- tures. This progression starts with small, slow limb movements whilst maintaining local system control. As the ability of the client to execute these movements improves, then an increased level of loading is introduced. The therapist observes and palpates for alignment, stability and control during all exercises.

lacunar ligament

Figure 1: The anatomy of the inguinal canal

muscles are deeply located, with attachments to the spinal column that give them an influence over segmental stability eg. multifidus.

The conventional model of lumbo-pelvic stabilisation has been outlined by Richardson (1). The principles of lumbar segmental stabilisation are to facilitate muscular activity which provides support and controls inter-segmental movement. The specific aim is to selectively recruit the local system muscles in order to pro- vide stability with the spine in a neutral position. The exercises that are designed to facilitate this tonic muscle action are ini- tially executed at a low threshold of activation, with the spine in a neutral, non functional position. Although EMG evidence sug- gests that multifidus is not tonically active during static postures, trunk movements and gait (9), there is much evidence that sug- gests therapeutic benefit in isolated tonic contraction (10,11).

Several tools can be utilised to facilitate the selective recruitment of the local muscle system. Ultrasound scanning has been demon- strated to be a valid method of evaluating local muscle recruit- ment (12). It is a non invasive method that permits patients to visualise the contraction of transversus abdominus and multifidus. This on screen feedback can be an excellent method for athletes to quickly master contraction of the local system and this is a very clear and satisfying method of demonstrating this concept.

Pressure biofeedback is a less costly approach which provides an indirect method of assessing local muscle system function. As

Spermatic cord

PRACTICAL ASPECTS OF STABILITY TRAINING IN TEAM SPORTS From a practical perspective, it is very difficult to implement and assess segmental stabilisation in a team sport environment, where there may be in excess of fifty players. Local system train- ing using both pressure biofeedback and ultrasound scanning pro- duces variable results in this client group. Some athletes find it very difficult to isolate transversus abdominus and multifidus. Even in those athletes who can isolate the local system, contin- ued compliance with this training is difficult, unless the athlete is motivated by a history of back pain, largely because the exer- cises are so abstract from their sporting activities.

Most athletes prefer global stabilising programmes as the per- ceived higher workload is more familiar to their sports training. Therefore in team sports the key point of a stabilisation pro- gramme is not whether the athlete can isolate the transversus abdominus and multifidus, but whether they can perform dynam- ic and later functional exercises in a stable, controlled manner with the spine in neutral.

This preference for global stabilisation exercise also applies in the rehabilitation of athletes with mechanical low back pain. However it should be stated that this rationale doesn't apply where there is radiological evidence of anatomical dysfunction such as a her- niated disc, facet hypertrophy or spondylolysthesis; in these cases perseverance with the local system exercises should be enforced.

The variability in athlete's ability to selectively recruit the Local system means that practically, despite investing a substantial time period in facilitating isolated recruitment of the Local sys- tem during the early stages of back pain rehab, the ability to per- form isolated activation of transversus abdominus and multifidus is not the criteria for progression. Although over activity in the external oblique is discouraged by Richardson (1), if an athlete can progress to global stabilising exercises, they do, even if there is ultrasound evidence of co-activation of internal oblique and external oblique. More recent evidence is beginning to support this clinical observation (13,14).

Figure 1: Facilitation of transversus abdominus in prone using pressure bio- feedback

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Cholewicki and McGill (15) previously proposed that the spine is subject to reactive internal forces in response to sudden postural disturbances. The local system has been shown to activate early as a protective response to these perturbations (16). This may indi- cate that local muscle system function can be facilitated by exer- cises that involve isometric activation of the global system with

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