Walking-based physical activity interventions for the management of chronic musculoskeletal pain.

Abstract

Chronic musculoskeletal pain (CMP) is a major cause of morbidity, and one of the most common reasons for individuals to seek treatment in both the primary and secondary care settings. Physical activity interventions are a central component of the non-pharmacological management of such conditions. However, encouraging patients to exercise or increase their overall physical activity can be problematic. This can be due to a number of potential barriers, including a belief that some activities may cause pain or injury.

Walking is a form of exercise or physical activity that may potentially be effective at improving adherence to treatment recommendations; due in part to its relatively low impact, ease of accessibility and general acceptability. However, there is limited evidence which has sought to investigate the effectiveness of such interventions in patients with chronic musculoskeletal complaints. The central aim of this thesis was therefore to examine the role of walking-based physical activity interventions in this population. A number of different methodological approaches were used to address this aim. This included: (1) a systematic review of randomised and quasi-randomised studies examining walking-based interventions in participants with osteoarthritis (OA), fibromyalgia (FM) and chronic lower back pain (CLBP) (chapter two and chapter three); (2) a laboratory based pilot study examining the effects of a single bout of moderate intensity treadmill walking on experimentally induced lower-limb muscle pain (chapter four); (3) a randomised controlled trial (RCT) to determine the feasibility of using a structured, pedometer walking programme as an adjunct to a standard education and advice session in participants with CLBP (chapter five and chapter six).

In chapter two, two different approaches for assessing methodological quality were evaluated by comparing the United States Preventative Services Task Force (USPSTF) system with the Downs and Black numerical scale. Both tools were used to rate the studies included in the systematic review presented in chapter three. Inter-rater reliability for both tools indicated at least substantial agreement. Levels of agreement and the correlation between quality ratings were also good. However, the USPSTF system identified a small number of studies as “poor”, due to potential risks of bias which the Downs and Black scale did not. Further analysis revealed substantially greater pooled effect sizes in these studies compared to those rated as “fair” or “good”. On the basis of these findings, it was concluded that the use of numerical summary scores may not identify potential sources of bias associated with overestimations of treatment effect. A recommendation was also made that numerical summary scores should not be used to assess methodological quality in reviews of exercise interventions. The domain based USPSTF system was therefore used for quality assessment in the subsequent systematic review (chapter three).

In chapter three, 21 studies were reviewed and data from 13 were pooled for meta-analysis. Studies rated using the USPSTF system were generally of at least fair methodological quality. Significant differences in favour of the walking interventions were found for both pain and function. Further analysis revealed that these differences were generally found at short and mid-term follow-up only, and that these effects were slightly greater where walking was supplemented with a co-intervention. Importantly, the review also identified that the majority of the available evidence was comprised of supervised walking interventions of between six to eight weeks duration. On the basis of the existing evidence, it was concluded that walking-based interventions should be recommended for eligible patients with CMP, but should be supplemented with interventions aimed at increasing longer-term participation.

In chapter four, experimental muscle pain was successfully induced in fourteen healthy participants using repeated bouts of an eccentric heel raise exercise. Twenty-four hours post pain induction, participants were randomised to an exercise group (consisting of a single, 30 minute bout of treadmill walking at approximately 50% of predicted maximum heart rate reserve), or to a non-intervention control group. The findings from this preliminary data suggested a trend towards lower pain ratings in the exercise group at each time point. Further studies are justified and should examine the potential hypoalgesic effects of this exercise modality and the physiological mechanisms underlying these effects.

Chapter five and chapter six, present the findings from different aspects of the Back 2 Activity Trial, which examined the feasibility of using a structured, pedometer walking programme as an adjunct to a standard education and advice session for individuals with CLBP. Following a single advice session, 57 participants were randomised, using a 2:1 allocation ratio, to a walking or advice only control group. Participants in the walking group received an eight week walking programme using a pedometer to monitor step counts and set individual weekly step targets.

In chapter five, the methods used to handle the objectively monitored accelerometer data from all participants recruited to the study are presented. While the accelerometer methods used were found to be feasible, a number of potential modifications relevant to the design of future trials are suggested.

Analysis of the pedometer and other outcome measurement data in chapter six, suggested that a structured pedometer walking program, given in addition to a standard education and advice session, is a safe and acceptable intervention in this population, and appeared to be effective at increasing pedometer derived step counts and targets over the eight week intervention phase.

In conclusion, this thesis provides support for the contention that walking-based interventions are effective at improving pain and self-reported function in individuals with CMP. Such interventions which incorporate a goal setting component may also represent a potentially effective means of increasing physical activity levels in this population. This thesis has also highlighted a number of important issues which are critical to the accurate measurement of physical activity in this population. In addition, the long-term effectiveness of walking interventions, particularly in terms of important patient reported and health-related outcomes have not been widely examined and further investigation is warranted.

Date of Award	Oct 2012
Original language	English
Supervisor	Suzanne Mc Donough (Supervisor), G. David Baxter (Supervisor), Mark Tully (Supervisor) & J. Bradley (Supervisor)