Research Review by Dr. Shawn Thistle©

Date:

2004

Study Title:

Evidence of altered lumbopelvic muscle recruitment in the presence of sacroiliac joint pain

Authors:

Hungerford B, Gilleard W, Hodges P

Publication Information:

Spine 2003; 28(14): 1593-1600

Summary:

The aim of this study was to evaluate muscle activation patterns during a standing hip flexion task in patients diagnosed with sacroiliac joint pain (SIJP) and compare it with control subjects with no low back or pelvic pain.

Fourteen men (mean age 32.7 years) who reported unilateral pain in the posterior pelvic/sacroiliac region without pain above the lumbosacral junction for longer than 2 months were included in the study group. Positive results on the active straight leg raise and stork tests were also required for inclusion in this study. Surface EMG electrodes were used to record muscle activity at 7 sites during a standing hip flexion test done bilaterally.

The sites were: 1) mid-belly of adductor longus 2) long head of biceps femoris 3) tensor fascia latae 4) gluteus medius 5) gluteus maximus 6) lumbar multifidus and 7) the internal oblique.

The 14 subjects and 14 age-matched controls without a history of low back or pelvic pain performed standing hip flexion tasks while EMG recordings were made. Trials were performed on both sides to facilitate comparison of symptomatic and asymptomatic sides in the SIJP patients.

Pertinent Results:

  • when control subjects performed the hip flexion task, activation of the lumbar multifidus and internal oblique (IO) occurred BEFORE initiation of the task, while activation of the other muscles occurred AFTER the movement began - this indicates a feed-forward mechanism of activation in these muscles
  • in patients with SIJP - activation of the lumbar multifidus, IO, and gluteus maximus was significantly DELAYED on the symptomatic side compared to control subjects, and their own asymptomatic sides (although some delay was seen on this side as well)
  • further, in patients with SIJP, biceps femoris activity occurred BEFORE the movement - suggesting an alternative strategy to extend the hip in order to stabilize the pelvis (substituting for delayed gluteus maximus activation)

Conclusions & Practical Application:

In recent years, research has indicated that pelvic and lower back stability is governed in large part by the proper function of the muscular and myofascial system. There is enough evidence now to suggest that many low back pain sufferers have altered muscle activation patterns. This study further demonstrates this, albeit in a small group of subjects.

These altered activation patterns, particularly in IO and multifidus, reflect a dysfunction in the ability to properly stabilize the low back/pelvis region in preparation for movement. From a clinical rehabilitation perspective, this could have implications in the design and implementation of specific exercises to correct these dysfunctions.

Research investigating some of these exercise protocols is now being done and preliminary results have been promising. By correcting faulty motor patterns and "re-training" the motor systems of low back pain patients, the hope is to prevent future episodes of back pain that so many patients suffer.

From a practitioner's standpoint, focusing only on the treatment of pain in acute flare-ups in patients with recurrent low back/pelvic pain may be doing a disservice to our patients. In fact, despite all of our best efforts and successes getting patients "out of pain", the research shows that most cases of low back pain will recur. Many practitioners claim to search for the "underlying" causes of patients' complaints, yet continue to provide only passive care during acute exacerbations.

I am not debating the importance of this type of care and treatment, but I would hope that the prudent practitioner would take advantage of the current literature to start looking in more detail at the function of the overall musculoskeletal system, rather than local tissues and symptoms.nd to conduct well designed trials to answer important clinical questions such as the most effective treatment for low back pain.