Lower back pain is often associated with weak lower back muscles. Contrary to that belief, low back pain can also be caused by excessively tense muscles, as a result of fear of pain and avoidance behaviour.
A common feature when it comes to the discussion of lower back pain is the Erector Spinae muscle. (Refer to factbox). When this group of muscle tenses constantly, it becomes tight and is unable to relax. This leads to the arched back posture that people suffering from low back pain can have. This tensed muscle will limit a person’s movement into flexion or otherwise in lay man’s term- bending forward, due to fear or pain.
How does the physiotherapist find out your muscles are restricted because of fear or pain?
In order to assess this, a physiotherapist will carry out what is known as Flexion Relaxation Response (FRR). FRR involves the eccentric contraction of the erector spinae which helps the patient to achieve their full range. This occurs until the end of range where muscle activity decreases significantly. The spinal extensors then relax completely, leaving the flexion torque to be supported by the spinal ligaments.
Erector Spinae Muscle
A set of three overlapping groups of deep muscles highlighted in illustration (Iliocostalis, Longissimus, and Spinalis)
Situated along the spine
Forms the largest area of muscle on the posterior (back) of the human torso
These muscles varies in size and structure at different parts of the vertebral column
Erector Spinae muscles functions to straighten the back and provide for side-to-side rotation
What causes this movement impairment?
As soon as it is established that FRR is impaired, we need to examine the factors that limits the muscles from relaxing. Musculoskeletal conditions are often complex in nature and limiting factors can occur concurrently. It is primarily due to fear avoidance behaviour- that is limiting one’s flexion deliberately for fear of pain. This results in stiff joints in lower back and hips as well as tight and tense muscles in these two areas.
Tightness can be a sign of guarding, which is a maladaptive movement orchestrated by the brain. Guarding occurs out of fear which stems from a faulty belief system. An example of a faulty belief is that a disc can “pop” out if I bend forward, and it can “pop” back in if I arch my back.
Prior to engaging the lower back, the brain increases muscle activity to protect the body region. This is your body’s automatic mechanism to counter the ongoing pain that you are experiencing.
A specific example where guarding takes place is on the lower back when the erector spinae remains active and engaged even as the spine is flexed forward. The muscles should be switched off. The fact that it is still actively engaged is an indication of an abnormal movement and there needs proper intervention to address it.
What can I do to relax the tense low back muscles?
It is important to to find the root cause of why your muscles are tense and working too hard. How then do we treat such a condition? It has to be understood that treatment is never a ‘one size fits all’ approach. Adequate and accurate assessments coupled with clinical reasoning needs to be applied in order to choose the appropriate treatments for you.
A physiotherapist has to understand your conditions first before providing solutions. Also, it is not just the physical aspect that matters. There needs to be adequate support for mental wellbeing which promotes optimal recovery. A combination of cognitive-behavioral interventions with pain reduction strategies is part of a holistic approach in managing persistent pain.
So the next time you are experiencing lower back pain, it could possibly stem from your body’s behaviour and movements.
It should always be kept in mind that back pain is a personal and complicated experience for each individual. Seeking medical advice and opting for treatment from a professional may be the solution to manage your back pain woes.