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) and provide an up-to-date evidence overview for health professionals and the general public to help in understanding this potential relationship. This page will review the current literature for and against the link between inactivity and low back pain.

The main focus of our page is physical inactivity is the cause of low back pain

Definitions

Non-Specific Low Back Pain

According to the 2009 NICE Guideline, the lower back can be defined as the area between the 12th ribs and the buttock creases.[1] "Non-specific" low back pain is defined as low back pain not attributable to a recognisable, known specific pathology (e.g. infection, tumour, osteoporosis, fracture, structural deformity, inflammatory disorder, radicular syndrome, or cauda equina syndrome).[2]

Time frame of low back pain classification:[3]

  • Acute low back pain – 6 weeks or less of symptoms
  • Sub-acute low back pain – 7-12 weeks of symptoms
  • Chronic low back pain – more than 12 weeks of symptoms
[4]

Physical Activity and Inactivity

“Physical activity is defined as any bodily movement produced by skeletal muscles that results in energy expenditure.”[5] Physical activity includes activities of daily living, such as walking, housework, gardening, and work-related activities.[6] When an individual does not meet the recommended level of physical activity, he or she will be classified as physically inactive.


The 2013 NICE Guideline recommendations (UK Chief Medical Officers’ physical activity recommendations) for physical activity state the following:[6]

  • All adults aged 19 years and over should aim to be active daily
  • Over one week, daily activity should add up to at least 150 minutes (2.5 hours) of moderate intensity physical activity in bouts of 10 minutes or more
  • Alternatively, comparable benefits can be achieved through 75 minutes of vigorous intensity activity spread across the week or combinations of moderate and vigorous intensity activities
  • All adults should also undertake physical activity to improve muscle strength on at least 2 days per week
  • All adults 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 at least 2 days per week
  • Individual physical and mental capabilities should be considered when interpreting the guidelines, but the key message is that some activity is better than no activity


The World Health Organisation (WHO) has classified physical inactivity into two levels.

  • Level 1 exposure (inactive): an individual does very little or no physical activity at home, work, for transport or in his/her private time
  • Level 2 exposure (insufficiently active): an individual does physical activity less than 150 minutes of moderate-intensity or 60 minutes of vigorous-intensity physical activity in all activities of daily living.[7]

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.[8]

Sedentary Behaviour

National guidelines classify people as sedentary when an individual does less than 30 minutes of moderate activity on all or most days of the week.[9] 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 mistaken as sedentary behaviour, such as slow walking, sitting, writing, and cooking, but these do require energy expenditure above the resting level.[10]

Epidemiology

Low Back Pain

  • One-third of 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[1]
  • 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% of people will have relapses of work absence after an initial episode of low back pain
  • Evidence has shown that the prevalence of chronic non-specific low back pain is around 23%, and 11-12% of the population is disabled by this condition[11]
  • 85% of cases are classified as non-specific low back pain as a diagnosis cannot be made by radiological methods[12]

Physical Inactivity

CouchPotatoes.jpg
  • Around the world, one in five adults are considered physically inactive
  • In developed countries, physical inactivity was found to be more prevalent in women and the elderly
  • Female physical inactivity was higher (21.4%) than male (18.9%)[13]
  • Approximately 60% of male adults, 72% of female adults, 68% of boys, and 76% of girls aged 2-15 do not meet the UK Chief Medical Officers’ physical activity recommendations[14]
  • Physical inactivity has been reported as the fourth leading risk factor for global mortality (6% of deaths worldwide)[15]
  • Around 3.2 million deaths each year are related to insufficient physical activity[16]

Health Complications

Physical inactivity and sedentary behavior can contribute to the following:[16]

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.[17]

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. A better understanding of what element or activity that a study is focused on, the easier it is to determine what outcome measure is most appropriate.[18]

Measurement of physical activity can be challenging. The outcome measures for physical activity are generally of two types - objective measures (e.g. accelerometers) and subjective measures (e.g. questionnaires). Each has a different degree of validity (i.e. the extent to which an instrument genuinely records what it is intended to measure),[19] reliability (i.e. how consistently an instrument or tool will measure something on two or more separate occasions),[20] feasibility and practicality. However, there is no ‘gold standard’ for assessing physical activity in public health settings.</span>[21][22][23]

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

  1. Measure of a specific type of physical activity
  2. Measure of the total physical activity
  3. Proportion achieving recommended physical activity levels

For more detail of each option, visit this link.

The table below shows the outcome measures available for traking physical activity:[24][25]

Objective Measures Subjective Measures
  1. Doubly labelled water
  2. Indirect calorimetry
  3. Pedometer
  4. Accelerometer
  5. Heart rate monitoring
  6. Geographical positioning systems (GPS)


  1. Self-report questionnaires
  2. Diaries or logs
  3. Direct observation




Outcome measure.jpg

Self-report approaches are the most frequently used method for measuring physical activity in a public setting due to its cost effectiveness compared 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.[26]

Below is a shortlist of selected questionnaires for physical activity and diet:[27][28]

Children and Young People

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 details of individual questionnaire, visit this link.

A recent systematic review by Falck et al. 2015 evaluated the measurement tools used in interventions to increase physical activity among older adults, including both objective and subjective measures. 44 studies were included, with 32 of them using self-report measures, 9 using objective measures, and 3 using both. Among all the measures, only 57% of them had population-specific reliability and 66% had population-specific validity. A majority of the studies used self-reported measures, even though many had 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. The advance in modern technology, the access to the technology for measuring physical activity, such as accelerometers and pedometers, is easier than ever, so future researchers should take opportunity to improve the quality of their studies by using better measurement tools. [29] 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 have been sensitive enough to measure the outcome. Furthermore, none of the tools can adequately detect change in physical activity over time, but capture more of a snapshot of a particular period of time.[30]

For Low Back Pain

Other Outcome Measures

Body Mass Index (BMI), physiological measures, and quality of life are frequently used as secondary outcome measures for physical activity. However, these outcome measures should only be used if they are relevant to the aims of the study or researcher’s interest.

Deconditioning

Cycle of Physical Inactivity Causing Low Back Pain

Cycle.png[32]

Bone Strength and Disc

Picture to show normal and osteoporotic bone
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 remodeling and increased resorption from osteoclasts.[33] Physical activity can influence bone mass by causing compressive or bending loads on bone. Bone formation will then be the resultant response from the strain/temporary deformation which will trigger primary and secondary responses in bone.[34] As such, being physically inactive may put one more at risk of having a low bone mineral density and consequently develope osteoporosis. However, current evidence still lacks high quality studies to confirm the inverse relationship between back pain and bone health.[35][36]

A 2015 study demonstrated a 'dose-response relationship' between physical inactivity, including narrow intervertebral disc height. Intervertebral disc narrowing is a feature of degenerative disc disease, suggested by some to be the single most important structural risk factor for low back pain.[37]

Musculoskeletal

Evidence suggests that in response to physical inactivity, skeletal muscles go through a process called adaptive reductive remodeling.[34] This results in a loss of muscle mass (atrophy) and changes in muscle composition. Muscle atrophy is characterised by a general reduction in muscle cross-sectional fibre area as well as a reduction in the overall number of muscle fibres,[38] leading to a decreased in muscle strength. Studies have shown that paraspinal muscles atrophy and increased in fat content are associated with low back pain from the result of physical inactivity.[39][37]

An example of high fat (50%) content of multifidus

Back extensor muscles

Metabolism

With chronic LBP patients who are deconditioned, their level of activity affects other parts of their body too. For instance, metabolic factors including carbohydrate and lipid metabolism will become less efficient and effective than healthy non-chronic LBP individuals.[34]

As a reduced physical activity level will eventually lead to weight gain and a change in body composition, people with LBP are reported to have a higher body fat percentage compared to age- and gender-matched individuals.[40] Obesity has been shown to have the strongest association with seeking care for low back pain.[41]


Factors Affecting Adults Participation in Physical Activity

Occupation

A person with a job that requires a relatively high demand of physical activity can be sedentary in his leisure time. However, although the physical activity guideline is met he/she may still be considered sedentary but physically active. On the other hand, a person with a sedentary job can be very active in his/her leisure time, and his/her physical activity may meet the guideline and he will not be classified as physically inactive. The type of occupation could affect the amount of physical activity, but it doesn’t necessarily have a direct influence on the physical activity one does during leisure time.

Original5 f1.jpg

The above figure demonstrates time trends for the prevalence of leisure time physical activity (LTPA) and work-related physical activity (WRPA). Values are from the Spanish National Health Interview Survey and are expressed as percentages.

Type of occupation

International research indicates that blue-collar employees typically exhibit lower rates of leisure-time physical activity. While “lack of time” and “work demands” are commonly reported barriers to activity, a secondary analysis of cross-sectional data from Australian Health Survey found out among the three categories of occupations (professional, white-collar, and blue-collar), individuals in blue-collar occupations were approximately 50% more likely to be classified as insufficiently active.[42]

Another systematic review found that white-collar/professionals demonstrated the highest leisure-time physical activity compared to blue-collar workers and concluded that there is convincing evidence that those employed in occupations demanding long work hours and low occupational physical activity are at risk of inactivity.[43] From both studies, they showed that there is an association between physical inactivity and type of occupation.

Sedentaryoccupational.jpg

Job Position, Job Stress and Psychological Distress

There are many factors that can affect a person’s physical activity. A cross-sectional study by Martins and Lopes (2013) investigated the association of rank (position of the job in an office setting), job stress, and psychological distress with physical activity in a military setting. The results showed that lower rank (‘high effort and low reward’) was associated with more occupational physical activity, more job stress, and with less physical activity in sports/physical exercise in leisure, and that psychological distress was associated with less physical activity in sports/exercise in leisure.[44]

Environment

The physical environment has a consistent association with physical activity behaviour. One review showed that accessibility, opportunities, and aesthetic attributes had significant associations with physical activity. Weather and safety showed less-strong relationships.[45] However, it is hard to isolate one factor from others, other variables affecting physical activity behaviour, and whether the changes is caused by the factor that the researcher is interested in is unknown. A better research model and measurement strategies is needed for future research.

Other Factors

  • Personal factors
    • enjoyment of exercise
    • expectation of benefits
    • intention to exercise
    • self-efficacy
    • self-motivation
    • social support from friends/peers/spouse/family
    • lack of time
  • Race/ethnicity
  • Social class etc.[46]

Evidence

Evidence For

A Dutch cross-sectional study from 2009[47] 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. An increased prevalence in LBP was also found in inactive participants with sedentary behavior. In addition, there is a potential gender-related risk for LBP in inactivity because the result is more significant in women compared to men.

U Shaped model demonstrating intensity of activity and risk of back pain

Another cross-sectional study from 2015[37] explored the association 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. Further details are explained in the following table.

Table to show findings from Teichtahl, et. al., 2015

Evidence Against

A systematic review written in 2011 reviewed 7 studies to look at if 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 studies in this area.[48]

Analysis for Sitthipornvorakul, 2011[49]

Limitations

The current literature looking at physical inactivity causing LBP are mainly cross-sectional studies. However, physical activity is continuous and patterns could change. Therefore, future longitudinal studies will help to better identify this cause and effect relationship.[50]

Furthermore, pain is complex and difficult to measure due to its subjective nature and it being a multidimensional experience. There is no external reference or gold standard.[51]

Physical activity is generally measured using self-reported questionnaires, which can lead to overestimation or underestimation. People generally tend to overestimate physical activity and underestimate sedentary behavior[52], which reflects the reliability and validity of questionnaires. A more sensitive alternative to questionnaires would be to use objective instruments such as pedometers, acceleometers, or heart rate monitors.

Interviews

An interview with Grahame Pope, the Head of Physiotherapy Education at University of Nottingham


An interview with Eric Bandoo, a band 6 Physiotherapist at Nottingham Citycare trust

Clinical Bottom Lines

There is numerous up-to-date literature about whether or not physical inactivity is responsible for LBP; however, more high quality longitudinal studies are needed.

IN summary, the reviewed literature is conflicting and inconclusive. Although there are only weak and conflicting results to link physical inactivity and LBP, there is strong evidence that leads to a poor general outcome. In the future, a more reliable objective measure is essential to ensure a reliable and valid outcome.

References

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