Effect of Encouragement on Six Minute Walk Test Performance

Peripheral artery disease (PAD) is characterised by a build up of fatty plaque in the arteries in the lower limbs, resulting in a reduction of blow flow to the muscles. Globally, it is estimated that 236 million people are living with PAD. A classic symptom of PAD is intermittent claudication (IC) which is characterised by muscle cramps in the lower limbs, typically brought on by exercise and relieved at rest. Exercise is recommended at first line treatment for IC. However to assess IC symptoms in response to an exercise study, maximal walking capacity (the furthest they can walk before it becomes too painful to walk) is typically the main measure. A patients walking capacity is assessed by a number of exercise testing protocols including the six-minute walk test (6MWT), where patients walk for six minutes with the aim to walk as far as they can in the time allotted. Patient encouragement has been shown to improve walking performance by as much as 30 meters in heart failure and respiratory disease populations. However the effect of encouragement on walking performance in people with IC is yet to be studied.

Peripheral artery disease (PAD) is characterised by atherosclerotic lesions of the arteries in the lower limbs, resulting in a reduction of blow flow (Hiatt, 2001). Globally, it is estimated that 236 million people are living with PAD, with the number of cases increasing by 24% from 2000 to 2010. A classic symptom of PAD is intermittent claudication (IC), characterised by ischemic muscle pain precipitated by exertion and relieved by rest. IC is associated with various comorbidities such as diabetes mellitus, hypertension and dyslipidaemia as well as reductions in physical function, quality of life, and balance. National and international guidelines recommend supervised exercise therapy as first line treatment for patients with IC.

To assess IC impairment in response to an exercise intervention, maximal walking capacity is typically the primary outcome in randomised controlled trials (RCT's). This involves a patient walking for as long as possible until ischemic leg symptoms, fatigue or other symptoms prevent them from continuing. This is assessed by a number of exercise testing protocols including the six-minute walk test (6MWT). The American Thoracic Society provide guidelines for performing a standardised 6MWT including verbal phrases that are conducted every minute. Conversely, Montgomery and Gardner suggest encouragement every two minutes. Encouragement has been shown to significantly affect walking performance by as much as 30 meters in heart failure and respiratory disease populations. However the effect of encouragement on walking performance in people with IC is yet to be investigated.

Eligibility Criteria:
Inclusion Criteria:

1. \>18 years old
2. Resting ankle brachial pressure index (ABPI) \<0.9 or a reduction of ≥ 20 mmHg following exercise testing (per site protocol)
3. Able to walk unaided
4. English speaking and able to follow exercise instructions
5. Able to provide informed consent

Exclusion Criteria:

1. Those who have critical limb threatening ischaemia (rest pain and/or tissue loss)
2. Unable to provide consent
3. Those presenting with any significant comorbidities or contraindications to exercise testing or training in accordance to the American College of Sports Medicine
4. Uncontrolled or symptom limiting coronary heart or pulmonary disease