Types of participants.

Studies reporting on adults (≥18years) with PAD and IC were eligible. To be included, all study participants must have been specifically diagnosed with IC. Diagnosis could have been by having Fontaine stage II PAD, or its equivalents, or if it was stated that only patients with IC were included in the study. Studies with participants having critical limb ischemia (rest leg pain, ischemic tissue loss, or an ABI<0.4) were excluded.

Types of studies.

Quantitative, qualitative and mixed methods studies in English language literature were eligible if published in peer review journals, or conference proceedings, and reporting primary data on barriers, enablers, facilitators or motivators for walking exercise and/or physical activity in IC. In addition to studies which examined the barriers or enablers for walking (either cross-sectional or longitudinal), studies reporting on experiences of living with IC were included if they specifically mentioned barriers or motivation or facilitators to walking. Also eligible were intervention studies that reported on factors influencing walking outcomes.

Context.

Studies with any cultural, healthcare, geographical, or community contexts were included.

Data management.

Studies were exported to remove the duplicates in Refworks™ and then exported to Microsoft Excel. Two review authors (UA, EE) read the title, and abstract, followed by full text to identify eligible studies against the previously defined eligibility criteria. Studies without a self-report or objective finding on factors related to walking, or studies without a homogenous sample of individuals with IC were excluded. In cases of divergence in analysis of eligibility decision, studies were discussed until a consensus was reached, or a third author (CS) was consulted.

Person related barriers.

Comorbid health factors: Comorbid health concerns were the most frequently identified barriers among participants. These barriers were reported by four (80%) of the qualitative studies[39–41,43] and were examined by nine (75%) of the quantitative studies[42,44,45,47–50,52,55] and the mixed method study[38]. Participants across the qualitative and mixed methods studies cited preexisting medical conditions and comorbidity as barrier to engaging in walking exercise[38–41], or dropping-out from a SEP program[43].The nine quantitative studies examined baseline factors associated with engaging in walking exercise and physical activity[42,45,47] or predictors of walking outcomes following SEP intervention[48–50,52]. Barbosa et al. reported that comorbid health conditions were a prevalent barrier to physical activity in 77 (51%) of their participants[45]. Diabetes was associated with decreased physical activity[45], lack of physical energy, personal barriers to physical activity[42], and was a predictor of poorer pain-free and maximum walking distances[47]. Similarly, higher BMI independently predicted lower improvement in pain-free[48] and maximum walking distance[52], and obesity predicted lower physical activity levels[45], and poorer improvement in both pain-free and maximum walking distance in men with IC[49]. Other comorbid conditions reported as barriers to physical activity included hypertension, arthritis, angina[45], and metabolic syndrome[45][50]. Participants across several studies also reported avoiding walking exercise or physical activity due to fear of falling, fatigue, injury or other adverse health issues[40–42,44,45,55].

Low walking capacity (walking capacity is the distance or length of time patients with IC can walk before pain symptoms are felt, or the pain experienced causes them to stop walking): Participants in one qualitative study reported that low walking capacity prevented them from moving around[46]. Seven quantitative studies examined the association between participants’ walking capacity measures and physical activity, or the role of participants’ walking capacity in mediating walking outcomes following SEP. These studies all indicated that low walking capacity was associated with lower physical activity[42,45,47], and lower pain-free and maximum walking distances following SEP, especially in women[49,50,52]. Also a lack of physical energy or inability to exercise at appropriate level was associated with decreased in walking exercise engagement[45][54].

Lower ABI: Two quantitative studies reported lower ABI as a barrier. Low ABI was associated with “some difficulty in getting to a place where physical activity can be performed”[42]. Similarly, poorer ABI predicted poorer improvement in 6-minutes walking distance of participants after a home-based exercise program[50]

Age: Participants in one qualitative study cited age as a barrier[41]. Three quantitative studies reported older age (>65 years) was a barrier to more physical activity engagement[42], and was associated with lower physical activity[45], or poorer improvement in pain free walking distance after SEPs[48].

Female gender: Three quantitative studies examined the influence of gender in ambulatory outcomes during and/ or after SEP. These studies showed that being female was associated with relative poorer improvement in pain free walking distance[48,49]. Also a lower mean exercise cadence predicted poorer pain free and maximal walking distances only in female participants[50].

Current smoking history: Three quantitative studies examined current smoking history as factors influencing walking ability or walking exercise engagement. Current smokers had lower pain-free walking distance than non-smokers[51]. Current smoking also predicted lower maximal walking distance following an exercise program[52]. Finally, current smokers had a lower mean attendance at exercise sessions compared with non-active smokers[54].

Lack of knowledge: Three major themes relating to lack of knowledge as a barrier to walking exercise were identified by the qualitative studies. The first theme was that participants did not engage in walking exercise because they lacked understanding of the pathology of IC[40,41]. The second theme was the lack of understanding and uncertainty regarding walking guidelines or suitable therapeutic walking dosages[41]. The third theme was that participants did not understand, or were uncertain, regarding the benefit of walking exercises, and how risk factors work[39–41,45,55]. Similar to this was participants’ outright disregard of walking as a treatment for IC[40]: “There’s no treatment. I’m getting no treatment, not for this. I’m getting advice, and the advice is ‘try to walk through it’. That’s the only advice I’ve ever had”[40]. Incidentally, the quantitative studies found that lack of knowledge was associated with low education level[42], and also that it predicted walking intention[53].

Perceived lack of improvement: One mixed methods study[38] and two qualitative studies[40,41] reported perceived lack of symptom improvement or lack of confidence that walking was providing any benefit as a barrier to walking exercise. Also, one quantitative study reported that subjective feelings of supervised training not providing any benefit was a barrier to participants continued attendance at SEPs[54].

Lack of time: The barrier of lack of time was identified in two quantities and three qualitative studies. Reasons for lack of time included associated burden of a hospital-based SEP[40,43], having other responsibilities such as caring for the grandchildren or elderly relative[43], and the need to “plan walking activity to avoid hills and allow greater time”[41]. Participants in two studies however, were not specific and stated generally perceived time constraints[39,45].

Other personal barriers: Other barriers reported included not having many symptoms generally or following invasive therapy[38], lower socioeconomic status[42,45], “feeling of isolation, and dependence, missing previous life and conforming to restricted life”[46].

Walking activity related barriers.

Walking induced pain: Walking-related claudication pain limitation was the most frequently identified behavioral barrier. Ten studies representing the only mixed method design[38], all (100%) of the qualitative[38–41,46], and four (33%) of the quantitative studies[42,45,53,55] reported pain related to walking as a barrier. Participants in the qualitative and mixed method studies commonly cited leg pain, discomfort or the need for frequent stops due to leg pain as a barrier to engaging in walking exercise or walking to a therapeutic intensity. Barbosa et al[45], a quantitative study, investigated the prevalence and predictors of barriers to physical activity, and showed that exercise-induced pain was the most frequently reported personal barrier. Also the need to rest because of pain predicted lower physical activity[45]. Another quantitative study[42], which investigated the relationship between barriers to physical activity and the sociodemographic and clinical characteristics of the participants identified needing to rest due to pain as a barrier. The third quantitative study investigated mediators of walking exercise and reported that people who experience bilateral claudication pain had weaker intention to walk than those with unilateral pain[53]. The fourth quantitative study[55] investigated barriers to PA and reported walking limiting pain as the most important barriers among participants.

Fatigue: Two quantitative studies reported fatigue (also described as “lack of physical energy”) as a significantly prevalent barrier[42,45] that was associated with declining physical activity[45] among participants. Similarly, participants in one qualitative study[39] indicated that they do not engage in walking exercise due to fatigue and low energy levels.

Lack of motivation: Lack of self-motivation to exercise (also described as “lack of confidence” “lack of conscientiousness” or “lack of interest” by researchers) was another behavioral barrier frequently identified among participants in qualitative[39–41], and mixed method studies[38]. Also, one quantitative study[54] showed that lack of interest in exercise was the second most frequent reason given by participants for non-attendance in a community-based SEP.

No walking advice or lack of specific walking advice: Two qualitative studies[40,41] and one mixed method study[38] reported barriers related to receiving advice; two major themes emerged from these studies. The first theme was that participants did not engage in walking exercise because they did not receive instruction to walk from the health professionals[38]. The second theme was that the instructions given by the health professionals were neither specific, tailored, purposeful nor accompanied with any walking plan[38,40,41]. Interestingly, lack of advice or lack of specific advice as a barrier to walking exercise was not examined as a potential barrier in any of the included quantitative studies.

Lack of supervision: One mixed method study noted lack of supervision during walking exercise was a barrier to continuing in walking exercise[38]. Lack of monitoring during physical activity was reported as a prevalent barrier in one of the quantitative studies[45]. No qualitative study investigated lack of supervision as a barrier to engaging in walking exercise/physical activity.

Environment related barriers.

Adverse weather conditions: Inclement weather was the most frequently identified environmental barrier. Unfavorable weather/season (e.g. winter) emerged as a barrier to walking exercise among participants in two qualitative[39,41] and one mixed method studies[38]. Also two quantitative studies[42,45] reported unfavorable weather as a barrier to participants engagement in physical activity.

Lack of/poor walking surface/obstacles that worsen pain: Absence of, uneven or poorly maintained pavements, or the presence of slopes or stairs were cited as barriers to walking[41,42,45,46]. Also, the presence of obstacles that exacerbated leg pain and not having a place to rest/sit when experiencing leg pain were reported as barriers associated with lower physical activity[42,45,55].

Lack of green areas/neighborhood/local facilities to engage in physical activity: Two quantitative studies reported lack of green areas, or not having facilities including SEP centers as a barrier to engage in walking exercise[42,45]. Similarly, participants in one study indicated security concerns and concern posed by vehicle movements as barrier to engaging in physical activity[45].

Person related motivators.

Belief that walking exercise could be beneficial: Belief about the potential benefit of walking was reported as enabler in two qualitative studies[40,41], and one mixed method[38] study. Participants indicated that their belief that walking could improve, slow down the deterioration of symptoms, and or potentially replace higher risk interventions, motivated them to engage in walking exercise.

Perceived improvement: Two themes related to participants’ perceived improvement as a motivator emerged from one qualitative[41] and one mixed method[38] study. The first theme was that participants belief in potential improvement or perceived improvement in general health motivated them to continue walking exercise[38]. The second was that participants’ perceived improvement in claudication symptom motivated them to continue walking exercise[38,41].

Other motivators: Other personal motivators identified include good understanding about IC, family history of serious vascular disease like amputation acting as warning[38], history of ischemic heart disease or hypercholesterolemia[54], and good baseline maximal walking distance[52].

Walking behavior related motivators.

Walking advice: Themes related to walking-related advice as a motivator to walking were reported in three studies. Receiving advice was the most important determinant of patients undertaking walking exercise[38]. Further, participants indicated that their desire to follow the walking advice provided by the health professionals motivated them to engage in walking exercise[38]. Also, participants in two qualitative studies indicated that a specific, purposeful, and tailored instruction about walking was a motivator to them to engage in walking[40,41].

Using cognitive strategies: Cognitive strategies as a motivator was identified in three qualitative studies and three subthemes were described. The first subtheme was related to planning walking into daily life[40]. The second subtheme was that objective walking goal setting enabled participants to actually undertake walking [46]. The third subtheme was that participants were able to continue to walk in spite of pain using mental (e.g. positive self-talks) and behavioral (e.g. stopping to take breaks) pain-coping strategies[39]. Similar to the cognitive strategies, two studies reported that participants’ perceived behavioral control[53], and having the intention to walk[39] were strong motivators for them undertaking walking.

Environmental related motivators.

Support system: Two qualitative and one mixed method study reported three subthemes describing support systems as a motivator to engaging in walking exercise. The first subtheme was the social and emotional support, including companionship, provided by family members and animal pets[38,39,46]. The second subtheme was the group members’ support systems (derived from e.g. a group exercise program or patient support groups)[38,39,46]. The third subtheme was the encouragement and support given by the health and social care professionals[39,40,46].

Availability of SEP: Availability of supervised exercise program was identified as a motivator to engaging in walking in two qualitative studies[39,40].

Others: Other environment related motivators identified include supervision and/or some form of monitoring[40], and having place to rest when having leg pain[46]