Low back pain (LBP) is a highly prevalent (9.4% of global population in 2014) health issue that affected approximately 83 million people globally in 2010. LBP has significant socioeconomic and healthcare implications and ranks the highest disorder in years lived with disability. There are several risk factors associated with LBP and some LBP conditions are worse than others. Mechanical, or nonspecific, LBP is the most common subtype of LBP and is one of the main reasons why patients seek medical or conservative management. Owing to the complexity of mechanical LBP, there is no universally accepted management protocol. However, health practitioners have a variety of tools to manage LBP. One type of management strategy supported in the literature is movement, i.e., the more movement or mobility patients maintain before, during and after their LBP episode, the better their prognostic outcomes will be. Backward bending (extension), in the lumbar (lower back) spine has shown to be a simple, but effective exercise strategy in LBP patients.
Spinal mobility and LBP
The spine is a remarkably strong, yet flexible structure supported by many contractile and inert structures such as muscles and tendons, ligaments, capsules and cartilaginous tissues. The spine favours movement in all ranges (i.e., forward and backward bending, rotation and side bending) and exercise is safe and effective for individuals with LBP. There is substantial evidence in the literature that supports the use of exercises aimed at improving spinal flexibility and muscle strength for patients with LBP. The more flexibility you have in your spine, the better your outcome will be. This is because spinal flexibility exercises maximally reduce the biomechanical stress placed upon the spine and surrounding soft tissue structures while you perform all ranges of movement, and also improves functional recovery times.
Sedentary lifestyles and flexion dominance
Physical inactivity has been linked to a variety of public health problems, including mechanical LBP. According to the 2011-12 National Health Survey, 63% of Australian adults aged 18 years and over were either overweight or obese, and this rate has increased over time. In 2011-12, adults spent an average of just over 30 minutes per day doing physical activity. However, against the National Physical Activity Guidelines for adults “to do at least 30 minutes of moderate intensity physical activity on most days”, only 43% of adults actually met the “sufficiently active” threshold.
In the same study, sedentary activity was found to occupy an average 39 hours per week for Australian adults, with close to 10 hours of this sitting at work. People employed in more sedentary occupations such as clerical and administrative workers spent on average 22 hours a week sitting for work. Watching TV was the most prevalent sedentary activity, at nearly 13 hours a week, peaking at over 19 hours per week on average for people aged 75 and over. Using the computer or Internet (for non-work purposes) peaked at almost 9 hours per week for 18–24 year olds.
These lifestyle and work factors encourage forward bending (flexion) of the lumbar spine. We slump into awkward positions that are held for vast amount of times throughout the day. This places a great deal of biomechanical stress on structures in the back. This increased flexion dominance reduces the spine’s ability to extend backwards, resulting in reduced mobility and increased risk of injury.
Directional preference in LBP
Patients with LBP will often present with a directional preference, i.e., a direction of movement that they favour and that may even decrease their LBP. It would be logical to assume that exercises encouraging extension would be beneficial in patient with LBP who have increased sedentary behaviours and lumbar flexion dominate lifestyles. Indeed, LBP is highly associated with lower lumbar extension strength. The literature supports the use of lumbar extension exercises for LBP management and disability. In fact, extension exercises are more favourable than the use of manipulations and Mulligan belts for gliding.
While extension may be helpful for the majority of people, there will be some individuals who favour other directions, and so this is not a one size fits all situation. Management is highly dependant on the individuals presenting condition, physical examination, and needs at that point in time.