PELVIC MUSCLE IMBALANCE

and has been linked as a possible cause of insufficiency with aerobic efficiency, aerody- namics, power and injury prevention.

THE MUSCLES Skeletal muscles can be categorised into two groups, phasic or postural, based upon their major functional tendency. The cur- rent thinking based on research into mus- cle function is that postural muscles under load or stress will tend to shorten whereas phasic muscles under load or stress are likely to weaken. For characteristics of the two types of muscles see table one. There is not the space here to go into a more detailed analysis of this theory however it is important to note that predisposition to the muscle type can be modified in some muscle groups depending on the stimulus (7,8,9,10,11,12).

The following muscles are involved in the soft tissue pelvic condition: Postural muscles ■ Hamstrings (Fig 1) ■ Hip flexors (Fig 2) ■ Triceps surae (not shown) ■ Erector spinae (Fig 3) ■ Quadratus lumborum (Fig 3)

■ Piriformis (Fig 2) ■ The short adductors (Fig 4).

Phasic muscles ■ Tibialis anterior (not shown) ■ Gluteus maximus and medius (Fig 2) ■ Vastus medialis and lateralis (Fig 2) ■ Gluteus minimus (Fig 2) ■ The long adductors (Fig 4).

ASSESSING INJURY In the assessment of the soft tissue com- ponents the range of movement in the fol- lowing muscles needs to be observed. They need to be compared bilaterally to find out what muscle groups are restricted: ■ Hamstrings versus quadriceps ■ Hip flexors versus erector spinae ■ Hip abductors versus hip adductors ■ Internal rotators versus external rotators

■ Iliotibial tract versus peroneals/tibialis anterior (lower leg).

The soleus and gastrocnemius of the calf should also be examined. If there is restric- tion to one or more groups of

these

muscles, then it places increased load and tension on other groups.

TABLE 1 CHARACTERISTICS OF POSTURAL VERSUS PHASIC MUSCLES (9) Phasic

Postural Type:

Respiration: Function:

Dysfunction: Treatment:

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Slow twitch (white) Anaerobic

Static/supportive Shorten

Lengthen

Fast twitch (red) Aerobic

Phasic/active Weaken

Facilitate/strengthen

Structural assessment The current osteopathic types of structural assessment procedures are enhanced through the use of muscle energy tech- niques to address pelvic anomalies (6). This involves measuring differences of the bony prominences at the pelvis and lower extremities. The structural assessment should reveal associated soft tissue restric- tions to be treated. The treatment plan is then determined on the outcome of the physical assessment.

Functional leg length discrepancies are commonplace when treating a pelvic imbalance and there is an opportunity to correct the length discrepancy (6). It is important to make sure the difference is structural and not functional before imple- menting the changes. Proper physical assessment is needed to establish if a structural or functional discrepancy is pre- sent. There are two types of discrepancies with assessment, causes and treatment options.

Structural differences Structural differences occur when different length osseous (bones) structures are pre- sent (4).

Assessment X-ray of lower extremities. Measurement of bony landmarks and other techniques. Possible causes Congenital from birth or surgery. Femoral/tibial length differences. Treatment Correction using heel lift orthotic inserts or orthopaedic shoes. Correction is possibly

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