A Novel Intervention to Promote Engagement in Physical Activity for Individuals With Whiplash Associated Disorder

Approximately 50% of adults who have a whiplash injury experience ongoing pain and disability from whiplash associated disorder (WAD). Causes are multifactorial, with considerable variation. Studies evaluating interventions for this population have used group-level design and analysis and, to date, findings have been equivocal and optimal treatment remains a challenge. In addition to pain and disability, patients are frequently insufficiently active for good health, increasing their risk of preventable morbidity and mortality, and compounding the effects of WAD. The proposed study will evaluate an intervention with two novel features. Firstly, the focus is not directly on the reduction of neck pain and disability, but aims to evaluate whether evidence-based health promotion/behavior change strategies can be successfully applied to increase physical activity promotion in this population. The investigator's hypothesis is that the intervention will not only increase participation in health enhancing physical activity, but through that engagement, patients will gain increased confidence to engage in activity in the presence of neck pain, thereby reducing pain-related disability. Secondly, the Single Case Experimental Design enables individual level analysis that is not possible with typical group level designs, including identification of characteristics of responders and non-responders.

Six participants will be recruited in two groups of three participants. Each group will comprise three participants who receive the same 16-week intervention (B) and 5-week follow up (maintenance), but have different lengths of the baseline period (A). The participants will be randomly allocated to one of the two groups, then subsequently randomly allocated to a baseline of either 5, 8 or 11 weeks. All participants will begin the baseline phase during the same week. Concurrent enrolment will minimize environmental influences and enhance internal validity (Kazdin, 2011). Experimental control is demonstrated by using the staggered multiple-baseline design across the participants, which controls for threats to internal validity (e.g., history, maturation) (Kazdin, 2011). The added feature of randomisation strengthens the scientific rigor of the study (Kratochwill and Levin, 2010). The design also allows for three demonstrations of the experimental effect (i.e., increased PA following the introduction of the intervention, but not before), and replication in a second group of participants (Kazdin, 2011).

During the baseline data collection period (A) participants will be encouraged to undertake their usual behaviour. Target behaviour measures (eg primary outcome measures) will be collected weekly during the baseline phase. Individual variability is addressed by repeated measurement of the target behaviour, and specifically, five data collection points within each phase is recommended to effectively evaluate a SCED intervention (Kratochwill et al., 2013).

The 16-week intervention period (B) comprises 12 one-hour intervention sessions (described below). An Accredited Exercise Physiologist (AEP) with experience in exercise prescription for individuals with a disability and behaviour change strategies associated with increasing PA will deliver the intervention. During the intervention period, the target behaviour measures will be collected fortnightly.

The intervention phase will be followed by a 5-week follow up phase where participants will have no contact with the AEP and target behaviour measures will be collected weekly. The maintenance component allows the target behavior to be monitored after the completion of the intervention, with the expectation that the target behavior will not revert to baseline levels after the intervention completion (Tate et al., 2015).

Generalisation measures (eg secondary outcome measures) will be collected at the commencement and finish of the baseline data collection period (which coincides with the intervention start point), at the end of the intervention period (which coincides with the commencement of the maintenance period), and at the end of the maintenance period; totalling 4 sampling points throughout the study duration.

Eligibility Criteria:
Inclusion Criteria:

* Individuals with grade II or III whiplash of at least 3 months duration;
* Individuals living in the Brisbane, Gold Coast or Northern NSW region;
* Individuals with a neck disability index score (NDI) \>32% (e.g., indicative of a moderate disability);
* individuals deemed to be medically safe to participate in moderate intensity PA; and
* individuals currently not participating in structured sport or training for physical fitness; and not completing 30 minutes or more of moderate physical activity on 5 or more days per week.

Exclusion Criteria:

* presence of known or suspected serious spinal pathology;
* confirmed fracture or dislocation at time of injury (e.g., WAD Grade IV);
* nerve root compromise; and
* spinal surgery in the past 12 months.