Inactivity and Low Back Pain

Introduction

The aim of this page is to investigate the relationship of how physical inactivity can cause low back pain (LBP). Additionally we will review current literatures for and against the link of inactivity and low back pain. It ultimately aims to provide an up-to date evidence overview to health professionals and the public to help them to understand the link between.

Definitions

Chronic non-specific low back pain

According to Nice guideline 2009, the lower back can be defined as the area between the 12th ribs and the buttock creases. “Non-specific low back pain is defined as low back pain not attributable to a recognisable, known specific pathology (eg, infection, tumour, osteoporosis, fracture, structural deformity, inflammatory disorder, radicular syndrome, or cauda equina syndrome).” Low back pain is a very common condition, but when the symptoms do not resolve after normal expected tissue healing time the condition will become chronic.  Low back pain that lasts for longer than 7-12 weeks can be defined as chronic. Sometimes frequently recurring back pain is defined as chronic as the condition intermittently affects one for a prolonged period. 

Physical activity and Inactivity

“Physical activity is defined as any bodily movement produced by skeletal muscles that results in energy expenditure.” Physical activity includes activity of daily living, for example, walking, housework, gardening, and work-related activity. When an individual who does not meet the recommended level of physical activity will be classified as physically inactive.

The NICE guideline 2013 recommendations (UK Chief Medical Officers’ physical activity recommendations) for physical activity state that:

• All adults aged 19 years and over should aim to be active daily.
• Over a week, this should add up to at least 150 minutes (2.5 hours) of moderate intensity1 physical activity in bouts of 10 minutes or more.
• Alternatively, comparable benefits can be achieved through 75 minutes of vigorous intensity2 activity spread across the week or combinations of moderate and vigorous intensity activity.
• All adults should also undertake physical activity to improve muscle strength on at least 2 days a week.
• They should minimise the amount of time spent being sedentary (sitting) for extended periods.
• Older adults (65 years and over) who are at risk of falls should incorporate physical activity to improve balance and coordination on at least 2 days a week.
• Individual physical and mental capabilities should be considered when interpreting the guidelines, but the key issue is that some activity is better than no activity.

The World Health Organisation has classified physical inactivity into two levels. Level 1 exposure (inactive) means the individual does very little or no physical activity at home, work, for transport or in their private time. Level 2 exposure (insufficiently active) describe individual that does physical activity less than 150 minutes of moderate-intensity or 60 minutes of vigorous-intensity physical activity in all activity of daily living.

The current levels of physical inactivity are partly due to insufficient participation in physical activity during leisure time and an increase in sedentary behaviour during occupational and domestic activities [WHO: http://www.who.int/dietphysicalactivity/factsheet_inactivity/en/]

Sedentary behaviour

National guidelines classify people as sedentary when the individual does less than 30 minutes of moderate activity on all or most days of the week. Sedentary behaviour describes activities that do not increase energy expenditure significantly above the resting level, it includes activities such as sleeping, lying, watching television and other types of screen-based entertainment. However, light physical activity is often being mistaken as sedentary behaviour, activities like slow walking, sitting, writing and cooking actually requires energy expenditure above the resting level.

Epidemiology

Low back pain 

• One-third on the United Kingdom adult population is affected by low back pain each year.

• 20% (1 in 15 of the population) of people will consult a GP about their low back pain.

• In Europe, the lifetime prevalence of low back pain can be as high as 84%.

• After the first experience of low back pain, 44-78% people suffer relapse of pain again.

• 26-37% people will have relapses of work absence after an initial episode of low back pain.

• Evidence showed that the prevalence of chronic non-specific low back pain is around 23%, and 11-12% of the population are disabled by the condition.

• 85% of cases are classified as non-specific low back pain as a diagnosis cannot be made by radiological methods.

Physical inactivity 

• Around the world, a one in five adult is considered physically inactive.

• In wealthier and urban countries, women and elderly people, physical inactivity was found to be more prevalent.

• Female’s physical inactivity was higher (21.4%) than men’s (18.9%).

• Approximately 60% of male adult, 72% of female adult, 68% of boys and 76% of girls aged 2-15 do not meet the UK Chief Medical Officers’ physical activity recommendations. (See above)

• Physical inactivity has been reported as the fourth leading risk factor for global mortality (6% of deaths worldwide).

• Around 3.2 million deaths each year are related to insufficient physical activity.

Outcome measures

Outcome measures for physical activity

The outcome indicator should be chosen according to how well it measures the objectives of the study. Other important factors in choosing an outcome measure are the level of data required, the characteristics of the individual, group or population, time frame of interest and the available time and resources. 

Physical activity can be classified as a combination of frequency, intensity and duration. Any type of activity can be different in terms of the three different aforementioned elements, in other words, different in the volume of physical activity. A better understanding of what element or activity that the study is focused on, the easier to determine what to use as an outcome measure.

Measurement of physical activity can be challenging. The outcome measures for physical activity are generally grouped into two groups - objective measure (e.g. accelerometers) and subjective measure (e.g. questionnaires). And each has a different degree of validity, reliability, feasibility and practicality. However, there is no ‘gold standard’ for assessing physical activity in public health settings.

Validity: the extent to which an instrument genuinely records what it is intended to measure.

Reliability: how consistently an instrument or tool will measure something on two or more separate occasions.

Options for measuring physical activity suggested in Standard Evaluation Framework for physical activity interventions, published by the National Obesity Observatory.

1. A measure of specific type of physical activity

2. Measure of total physical activity

3. Proportion achieving recommended physical activity levels

(for more detail of each option, you can visit this link: http://www.noo.org.uk/uploads/doc/vid_16722_SEF_PA.pdf)

A table of the outcome measures for physical activity :

Objective Measures	Subjective Measures
Doubly labelled water Indirect calorimetry Pedometer Accelerometer Heart rate monitoring Geographical positioning systems (GPS)	Self-report questionnaires Diaries or logs Direct observation

Self-report approaches is the most frequently used method for measuring physical activity in a public setting due to its cost effectiveness compare to other outcome measures. However, their reliance on recalling activity can be problematic, especially for children and young people. Self report of physical activity is subject to a number of types of bias, such as recall bias, lack of compliance and ‘social desirability’ bias.

Shortlist of selected questionnaires for physical activity by NOO reviews of measurement of diet and physical activity

Physical activity: children and young people	Physical activity: adults
1. The Physical Activity Questionnaire for Older Children/Adolescents (PAQC/PAQ-A) 2.Youth Risk Behaviour Surveillance Survey (YRBSS) 3. The Teen Health Survey	1. Stanford 7-day recall (7-DR) 2. International Physical Activity Questionnaire Long version (IPAQ-Long) 3. New Zealand Physical Activity Questionnaire (Short Form) (NZPAQ-Short) 4. 7-day Physical Activity Diary

(For more detail of individual questionnaire, visit the link: http://www.noo.org.uk/uploads/doc/vid_10414_Assessment%20Tools%20160311%20FINAL%20MG.pdf)

A recent systematic review done by Falck et al. 2015, the aim of the review is to evaluate the measurement tools used in interventions to increase physical activity among older adults, including both objective and subjective measures. 44 studies are included, 32 of them used self-report measure and 9 used objective measures and only 3 used both measures. Among all the measures only 57% of them had population specific reliability and 66% had population- specific validity. A majority of the studies use self- report measures, even though many have little evidence of validity and reliability. The researchers of the systematic review suggested that future researchers should use valid and reliable measures of physical activity with well-established evidence of psychometric properties, for instance hip-accelerometers and the community Health Activities Model Program for Seniors Physical Activity Questionnaire for older adults. I strongly agree with the idea, as the advance in modern technology, the access to the technology for measuring physical activity, such as accelerometers and pedometers, is easier than before, future researchers should take the chance and improve their studies quality by using a better measurement tool. 11 On the other hand, it is important to note that most of the questionnaires were not developed for use in individual or group interventions, but population surveillance. In some cases, the tools may not be sensitive enough to measure the outcome. Furthermore, none of the tools can adequately detect change in physical activity over time, but a snapshot of a particular period of time. 1

Outcome Measure for Low Back Pain

- numerical rating scale (NRS)
- Roland–Morris disability questionnaire (RMDQ)
- Oswestry disability index (ODI)
- pain self-efficacy questionnaire (PSEQ)
- the patient-specific functional scale (PSFS)

Other Outcome Measures

BMI, physiological measures and quality of life are usually used to be a secondary outcome measure for physical activity. Such outcomes should only be measures if they are relevant to the aims of the study or researcher’s interest.

Biomechanics

Deconditioning

Body composition and bone strength

As a reduced physical activity level, eventually leads to weight gain and a change in body composition, patients with LBP are reported to have a higher body fat percentage compared to age- and gender- matched individuals. In addition, bone health is also likely to be affected in an inactive population. According to Wolff’s Law, if the loading on a bone decreases, the bone will become less dense and weaker due to the lack of the stimulus required for continued remodelling and increased resorption from osteoclasts. Conversely, if loading on a particular bone increases, the bone will remodel (increased osteoblast activity) itself over time to become stronger to resist that sort of loading. However, current evidence still lacks strong high quality to confirm the inverse relationship between back pain and bone health.

Verbunt, J.A., Seelen, H.A., Vlaeyen, J.W., Bousema, E.J., van der Heijden, G.J., Heuts, P.H. and Knottnerus, J.A., 2005. Pain-related factors contributing to muscle inhibition in patients with chronic low back pain: an experimental investigation based on superimposed electrical stimulation. The Clinical journal of pain, 21(3), pp.232-240.
Kriska, A.M., Saremi, A., Hanson, R.L., Bennett, P.H., Kobes, S., Williams, D.E. and Knowler, W.C., 2003. Physical activity, obesity, and the incidence of type 2 diabetes in a high-risk population. American Journal of Epidemiology, 158(7), pp.669-675.

Briggs, A.M., Straker, L.M. and Wark, J.D., 2009. Bone health and back pain: What do we know and where should we go?. Osteoporosis International, 20(2), pp.209-219.
Wolff, J., 2012. The law of bone remodelling. Springer Science & Business Media.
Briggs, A.M., Straker, L.M. and Wark, J.D., 2009. Bone health and back pain: What do we know and where should we go?. Osteoporosis International, 20(2), pp.209-219.

Evidence

Evidence for

A Dutch cross-sectional study from 2009 investigated the U-shaped relationship between physical activity and low back pain. The study concluded that both extremes of physical activity- excess activity or insufficient activity associated with a high risk of LBP (fig x). An increased prevalence in LBP was also found in inactive participants with sedentary behavior. In addition to that, there is a potential gender-related risk for LBP in inactivity because the result is more significant in women compared to men.

Another cross-sectional study from 2015 explored the associations between physical inactivity and intervertebral disc height, spinal muscles fat content and low back pain and disability. Results concluded that participants with lower activity levels had higher BMI, narrower intervertebral disc height, higher fat content of multifidus, increased risk of high-intensity pain/disability ratio after adjustment for age, gender and BMI.

Evidence against

A systematic review written in 2011 reviewed 7 studies to look at whether patients with chronic low back pain have an altered level and/or pattern of physical activity compared to healthy individuals. The gathered data revealed no significant difference in the overall activity level of adults (18-65 y/o) or adolescents (<18y/o) with chronic low back pain, however there is evidence that older adults (>65 y/o) with chronic low back pain are less active than controls. They concluded that there is no conclusive evidence that patients with chronic low back pain are less active than healthy individuals and there is a lack of number of studies in this area. 

Limitations

cross-sectional studies

-physical activity is continuous and intensity could change.
--> longitudinal design would be more reliable

-difficult to identify casualty
-->whether physical inactivity is causing low back pain or vice versa

-other factors which could influence low back pain
--> such as BMI and age

pain is a complex outcome measure: use questionnaires, could lead to overestimation or underestimation.

References

1. National Institute for Health and Clinical Excellence (NICE) (2009) Low back pain in adults: early management. [Online]. Available at: http://www.nice.org.uk/guidance/cg88/resources/low-back-pain-in-adults-early-management-975695607493. [Accessed: 9 January 2016].
2. Balagué, F., Mannion, A. F., Pellisé, F., & Cedraschi, C. (2012). Non-specific low back pain. The Lancet, 379(9814), 482-491.
3. O’Sullivan, P. (2005). Diagnosis and classification of chronic low back pain disorders: maladaptive movement and motor control impairments as underlying mechanism. Manual therapy, 10(4), 242-255.
4. Andersson, G. B. (1999). Epidemiological features of chronic low-back pain. The lancet, 354(9178), 581-585.
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12. National Institute for Health and Clinical Excellence (NICE) (2012) Physical activity: Local government briefing. [Online]. Available at: https://www.nice.org.uk/advice/lgb3/resources/physical-activity-1681146084805. [Accessed: 9 January 2016].
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15. Outcome measuress' references
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