Locomotor Slings : a New Total Body Approach to Treating Chronic Pain

Locomotor slings is a model which recognises that muscles and their investing fascia are frequently interconnected, with fibres blending from one muscle to the next. Groups of muscles and their fascia may be related by direct anatomical continuity, whereby a chain of muscles and their fascia are interconnected in a relatively continuous line. This chain of anatomically interconnected myofasciae is known as a ‘myofascial sling’. Alternatively, some chains of myofasciae are related functionally, meaning that they are almost always activated together to perform a motor task. These chains of myofasciae are called a ‘locomotor sling’. Both myofascial and locomotor slings consist of a chain of myofasciae spanning either a region of the body or from head to toe. They are involved in controlling both posture and movement. Consequently, when examining and treating abnormal posture and motion, clinical results may be improved by understanding the inter-relationships and organisation of myofasciae into slings. The Locomotor Slings approach provides an ideal model for practitioners of structural balancing and is complementary to existing models of clinical examination and treatment. The concept of a Locomotor Sling was created in an effort to explain why some groups of myofascial structures have a tendency to become tight, in order that treatment may involve not only improving the flexibility of these structures but also identifying and managing the underlying cause of the tightness. When considering the muscular system, its investing fascia is often neglected. This is surprising since fascia is a substantial structure that is inseparable from and in fact adherent to the underlying muscle. Thus it is impossible to palpate or otherwise manipulate muscle without influencing its overlying fascia and vice versa. Consequently a more appropriate term for the muscle-fascia unit is myofascia. Fascia is primarily a collagenous sheet of tissue and has been shown to contribute significantly to muscle function. For example, Garfin and co-workers (Garfin et al., 1981) demonstrated that simply incising the fascia reduces muscle strength by 15 per cent. Like muscle, fascia is richly innervated with mechanosensitive and nociceptive nerve endings (Yahia et al., 1992), suggesting that it also has an important sensory role. Thus fascia is not simply a passive structure present without purpose. It can adapt and remodel in response to stress in order to better meet the demands placed upon it. One of the interesting features about the myofascial system is that contrary to popular anatomical descriptions in which muscles are generally portrayed as having a unique and localised origin and insertion, muscles do not always insert onto a single unique location separate from all other muscles. Muscles frequently appear to have some fibres which blend across to the adjacent muscle, fascia or ligament. The fascia itself always blends with and is anatomically continuous with adjacent fascia. In fact, fascia is continuous throughout the human body (Juhan, 1987). A well studied example is the continuity between fibres of the plantar fascia of the foot and the Achilles tendon (Snow, Bohne, DiCarlo, & Chang, 1995), where collagen fibres have been shown to be continuous across the posterior calcaneum (Figure 1). Similarly, it has been well documented that the biceps femoris muscle frequently attaches not only to the ischial tuberosity but also to the adjacent sacrotuberous ligament (Vleeming, Stoeckart, & Snijders, 1989). Stripping of the investing fascia during dissection starts to strip away the interconnectivity that is otherwise readily apparent between adjacent myofascial and other connective tissue structures. The functional significance of these interconnections has been investigated but is not yet fully understood. For example, it has been shown that mechanical tension applied to the biceps femoris muscle is transferred to the sacrotuberous ligament to which it partially attaches (Van Wingerden, Vleeming, Snijders, & Stoeckart, 1993). In another example, a myofascial continuity has been described between the gluteus maximus muscle, the thoracolumbar fascia (TLF) and the contralateral latissimus dorsi muscle. Traction applied to the gluteus maximus muscle has been shown to be transferred across the TLF to the contralateral latissimus dorsi muscle (Vleeming et al., 1995). While it appears that studies such as these have established a biomechanical continuity between adjacent myofasciae, the significance of the shared fascia in terms of its sensory role has yet to be investigated. It is possible that the overlapping sensory supply may have a role in co-ordinating activity between related myofasciae.