Randomized clinical trial
Randomized clinical trial comparing Nordic pole walking and a standard home exercise programme in patients with intermittent claudication C. Spafford1 , C. Oakley1 and J. D. Beard2 1 Sheffield Nordic Walking Research, Steps Physiotherapy and Circulation Clinics, and 2 Sheffield Vascular Institute, Northern General Hospital, Sheffield, UK Correspondence to: Mrs C. Spafford, Steps Physiotherapy and Circulation Clinics, 32 Southbourne Road, Sheffield S10 2QN, UK (e-mail: [email protected])
Background: This was a randomized clinical trial to determine whether Nordic pole walking (NPW)
is more effective in improving walking distance than a standard home exercise programme (HEP) in patients with intermittent claudication. Methods: Fifty-two patients with stable claudication were allocated randomly to a standard HEP or NPW group, and asked to complete three 30-min walks per week for 12 weeks. Claudication distance (CD) and maximum walking distance (MWD) were measured at 0 (baseline), 4, 8 and 12 weeks. Patients in the NPW group were tested with (NPW+) and without (NPW–) poles. Results: For NPW+, CD increased immediately from a median (range) of 124 (71–248) m to 148 (116–426) m, and MWD from 248 (149–900) to 389 (194–1099) m (P = 0·004 and P < 0·001 respectively). By 12 weeks, CD had further increased to 199 (118–550) m and MWD had more than doubled to 538 (250–1750) m (P < 0·001 and P = 0·001). For NPW–, CD at 12 weeks had increased significantly to 151 (100–328) m and MWD to 400 (200–900) m (P < 0·001 and P = 0·006 respectively). At 12 weeks the changes in the standard HEP group were not significant, despite excellent compliance: CD from 107 (56–332) to 153 (59–321) m and MWD from 355 (92–600) to 334 (149–874) m (P = 0·030 and P = 0·260 respectively). Conclusion: A 12-week exercise programme using Nordic poles significantly improved walking distance in claudicants compared with a standard HEP. Registration number: ISRCTN78168304 (http://www.controlled-trials.com). Presented to a meeting of the Vascular Society of Great Britain and Ireland, Manchester, UK, November 2013 Paper accepted 26 February 2014 Published online 24 April 2014 in Wiley Online Library (www.bjs.co.uk). DOI: 10.1002/bjs.9519
Introduction
Peripheral arterial disease can limit blood flow to the legs on walking, causing intermittent claudication. The limited exercise capacity of these patients increases their risk of obesity and reduces cardiovascular fitness, which in turn increases their susceptibility to co-morbidities such as diabetes and cardiac disease1 . Walking advice alone is ineffective, as patients with claudication are usually non-compliant owing to a lack of support and motivation2 . Exercise therapy is less costly and carries a lower risk than radiological or surgical intervention. The proven benefits of exercise include improvement in walking distance, cardiovascular fitness, quality of life and life expectancy3 . 2014 BJS Society Ltd Published by John Wiley & Sons Ltd
Supervised exercise programmes have been found to be as effective as angioplasty4 , but are expensive to run and compliance may be as low as 34 per cent5 . Home exercise programmes (HEPs) are less expensive, and integrate more readily into the patient’s lifestyle6 , but there is a lack of quality evidence of the efficacy of HEPs compared with supervised exercise programmes. The greatest benefits are seen when patients exercise for a minimum of three times a week for 30 min, and walk to maximal pain levels7 . Unsupervised, but supported, exercise programmes in the community may be a good compromise in terms of both cost and compliance8 . Support in the form of telephone or online coaching and problem-solving, plus walking diaries and pedometers, may be the best way to increase patient BJS 2014; 101: 760–767
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reproducibility and reliability, and is more suitable for evaluating walking distance in patients with intermittent claudication17 . The primary aim of this study was to determine whether NPW was more effective in improving walking distance than a standard, supported HEP. The secondary aims were to compare calorific expenditure as a measure of cardiac workload, postexercise ABPI and compliance. Methods
Fig. 1
Nordic walking poles
compliance with exercise programmes6,9,10 . However, unlike revascularization, all current exercise programmes suffer from a lack of immediate benefit. Nordic pole walking (NPW) is an accepted form of exercise training for athletes (Fig. 1). NPW results in an increase in oxygen use (23 per cent) and calorific expenditure (22 per cent) compared with regular walking, without an increase in perceived exertion11 . NPW involves a significant contribution from the arm and shoulder muscles, which aid forward propulsion. It also reduces the load on the spine and legs when walking uphill or on the flat compared with ordinary walking12 . This may be an additional benefit as many patients with claudication also have arthritis of the spine, hips and knees. There is evidence that NPW improves cardiovascular fitness in many patient groups, including those with claudication13 , and is a suitable form of exercise for the older population14 . Nordic walking feels easier than normal walking, but works the cardiovascular system 23 per cent harder, as all muscles are used. There is also known psychological mood enhancement attributed to NPW15 . A pilot study by Oakley and colleagues16 in patients with intermittent claudication showed that NPW immediately increased walking distance on a treadmill, decreased leg pain, increased cardiovascular effort, and was perceived as being easier than normal walking. The study also showed that NPW caused a lower reduction in the postexercise ankle : brachial pressure index (ABPI), suggesting some offloading of the leg muscles. Most studies examining the effects of exercise in patients with peripheral arterial disease use a treadmill. Measuring walking distance on a treadmill is an accepted standard, but bears little similarity to the exercise patients experience in their daily lives. It has been suggested that the shuttle walking test is more representative, shows better interstudy 2014 BJS Society Ltd Published by John Wiley & Sons Ltd
The study was approved by the National Research Ethics Service Yorkshire and the Humber–South Yorkshire Ethics Committee (reference no. 11/YH/0100; protocol no. STH15454). The research study is listed in the UKCRN Portfolio database (reference 10781) and also registered with the ISRCTN Register (http://www. controlled-trials.com/ISRCTN78168304). Consecutive patients with stable claudication were referred from local vascular clinics over 12 months. A full medical history was taken and clinical assessment was carried out for each patient before enrolment in the study and documented on a pro forma, along with the demographic details. Patients were invited to attend a clinic appointment with a research physiotherapist, where the study was discussed in full, and informed consent was obtained. Height and weight were recorded, and patients were taught the technique of NPW. Each patient was then allocated randomly to either NPW or HEP (control group), using the fish bowl method, and given appointments to attend gym sessions for tests at 0, 4, 8 and 12 weeks. After the initial appointment, patients were given instructions on exercising at home. Patients in the NPW group were given a pair of LEKI (http://www.leki.co.uk) Nordic walking poles adjusted for height (height × 0·7) and asked to walk using the poles for at least 30 min three times per week. The HEP group was given written instructions to walk at their normal pace for at least 30 min three times per week. Both groups were given a pedometer (Yamaxx Digiwalker CW-700/701; http://www.yamaxx.com), and a diary to record the date, time and duration of each period of exercise, together with the pedometer reading (number of steps taken) and perceived exertion. Patients were shown (and given written instructions on) how to use the pedometers. They were supported by a weekly telephone call from one of the research physiotherapists. Diary entries and activity data were recorded when they attended the gym sessions. Patients’ diaries were monitored to determine whether any changes in walking distance were due to non-compliance. www.bjs.co.uk
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Enrolment
Referred from clinic n = 86 Excluded n = 25 Did not meet inclusion criteria n = 2 Declined to participate n = 23 Consented n = 61
Analysis
Follow-up
Allocation
Randomized n = 52
Fig. 2
Withdrawn after consent, before commencing study n = 9 Cancer n = 2 Cardiac n = 1 Back pain n = 1 Respiratory n = 1 General health deteriorated n = 1 Having surgery n = 1 No time n = 2
Allocated to home exercise programme n = 24
Allocated to Nordic pole walking n = 28
Withdrawn during study n = 5 Died (MI) n = 1 Had surgery n = 1 Ill health n = 1 No time n = 2
Withdrawn during study n = 9 Too good with poles n = 2 Ill health n = 2 No time n = 5
Analysed n = 19
Analysed n = 19
CONSORT diagram for the trial. MI, myocardial infarction
At each test session body mass index was calculated. Resting ABPI was taken before exercising using a hand-held Doppler. Blood pressure and heart rate were recorded at rest. Patients were fitted with a heart monitor chest belt (Suunto M2; Suunto, Vantaa, Finland) for each test. A modified shuttle walking test, consisting of walking a 50-m figure-of-eight circuit as fast as possible and for as long as possible, was then performed. The HEP group completed the test once, without poles. The NPW group did the test twice, once with poles (NPW+) and once without poles (NPW–), with a rest in between while their heart rate and blood pressure returned to normal. The order of the tests was allocated randomly at each visit, using the fish bowl method, to avoid bias. During each test, the following data were collected: claudication distance (CD) in metres, CD time (using a stopwatch), CD heart rate, maximum walking distance (MWD) in metres, MWD time, MWD heart rate, average heart rate, calorific expenditure, and rating of perceived exertion and pain (using Borg’s CR-10 scale). Time and distance were used to calculate walking speed in metres 2014 BJS Society Ltd Published by John Wiley & Sons Ltd
per second. ABPI, blood pressure and heart rate were measured immediately after exercise, then blood pressure and heart rate were retested every 5 min until the preexercise levels were reached. These tests were performed at 0 (baseline), 4, 8 and 12 weeks. The difference in distance walked with and without poles at the baseline assessment represented the immediate improvement in the NPW group.
Inclusion and exclusion criteria Included patients had stable intermittent claudication for at least 6 months, and a resting ABPI below 0·9. They were unsuitable for revascularization and/or had no revascularization procedure in the previous 6 months. The level of disease and unsuitability for revascularization had been determined previously by duplex ultrasound examination and/or magnetic resonance arteriography. Patients were excluded if they had other conditions that could limit their walking distance (such as breathlessness or severe osteoarthrosis). www.bjs.co.uk
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Table 1
Demographics of the patient cohort
Age (years)* Sex ratio (M : F) Body mass index (kg/m2 )* Level of PAD Calf Thigh Buttock Resting ABPI* Smoking status Current smoker Previous smoker Never smoked Antihypertensive medication Beta-blockers Previous operation COPD Ischaemic heart disease Previous stroke Diabetes Arthritis Statins Antiplatelet agents Warfarin
Total (n = 52)
Home exercise programme (n = 24)
Nordic pole walking (n = 28)
65(2) (39–84) 35 : 17 28(1)
65(2) 16 : 8 29(1)
65(2) 19 : 9 28(1)
49 (94) 2 (4) 1 (2) 0·61(0·03)
21 (88) 2 (8) 1 (4) 0·61(0·04)
28 (100) 0 (0) 0 (0) 0·61(0·03)
9 (17) 31 (60) 12 (23) 31 (60) 7 (13) 11 (21) 8 (15) 11 (21) 2 (4) 16 (31) 7 (13) 47 (90) 43 (83) 2 (4)
5 (21) 15 (63) 4 (17) 16 (67) 4 (17) 5 (21) 4 (17) 5 (21) 2 (8) 9 (38) 4 (17) 21 (88) 20 (83) 0 (0)
4 (14) 16 (57) 8 (29) 15 (54) 3 (11) 6 (21) 4 (14) 6 (21) 0 (0) 7 (25) 3 (11) 26 (93) 23 (82) 2 (7)
Values in parentheses are percentages unless indicated otherwise; *values are mean(s.e.m.) (range). Ankle : brachial pressure index (ABPI) data are presented for the most symptomatic leg. PAD, peripheral arterial disease; COPD, chronic obstructive pulmonary disease.
Statistical analysis There was no previous single study from which all the variables needed to perform an accurate power calculation could be obtained. The variables were therefore estimated by combining the results of previous studies, with MWD as the primary outcome. It was estimated that a sample size of 42 participants would provide 80 per cent power with an α value of 0·05 and an anticipated effect size of 0·8 (Cohen’s d). This sample size was increased to 50 to allow for a drop-out rate of 20 per cent (the usual rate for many claudication studies). Descriptive statistics were obtained and tested for normal distribution using the Kolmogorov–Smirnov test. The walking distance data (MWD and CD) violated the assumption of normality and could not be normalized using data transformation techniques, so non-parametric tests were used. The Wilcoxon signed rank test was used to analyse differences in walking distance and, as multiple comparisons were being made, the α level was set to P < 0·017 using a Bonferroni correction to reduce the risk of type I errors. Differences between groups were analysed using the Mann–Whitney U test. Differences 2014 BJS Society Ltd Published by John Wiley & Sons Ltd
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in calorific expenditure and resting ABPI were assessed using the Wilcoxon signed rank and paired-samples t tests respectively. Data were analysed using SPSS version 20 (IBM, Armonk, New York, USA). Results
Eighty-six patients with stable claudication, aged 39–84 years, were referred for assessment. Following referral, 25 patients were excluded from the study or declined to participate owing to travelling distance or time constraints. A further nine withdrew after consent but before commencing the walking (Fig. 2). Fifty-two patients were randomized (28 NPW, 24 HEP). Baseline characteristics were well balanced between the two groups (Table 1). After commencing the walking, a further 14 patients discontinued the study: nine in the NPW group and five in the HEP group (2 had more proximal disease). Two patients in the NPW group were withdrawn, as they failed to reach CD and MWD when using the poles on initial testing, and were therefore deemed too good for this study. In the HEP group, one patient died from myocardial infarction, but this was not while exercising. A total of 19 patients in each group remained for analysis.
Walking distance The primary outcome measure was walking distance: CD and MWD. The NPW group increased their CD immediately from a median (range) of 124 (71–248) m without poles (NPW–) to 148 (116–426) m with poles (NPW+) (P = 0·004, z = –2·90, r = 0·47), and MWD increased from 248 (149–900) to 389 (194–1099) m respectively (P < 0·001, z = –3·55, r = 0·58). At 12 weeks with poles (NPW+), CD had increased to 199 (118–550) m (P < 0·001, z = –3·58, r= 0·58), and MWD had more than doubled to 538 (250–1750) m (P = 0·001, z = –3·34, r = 0·54). Without poles (NPW–), CD had increased significantly at 12 weeks to 151 (100–328) m (P < 0·001, z = –3·78, r = 0·61) and MWD to 400 (200–900) m (P = 0·006, z = –2·77, r = 0·45) (Fig. 3). At 12 weeks, increases in the standard HEP group were not significant, despite excellent compliance; CD changed from 107 (56–332) to 153 (59–321) m (P = 0·030 (not significant with Bonferroni correction), z = –2·17, r = 0·35) and MWD from 355 (92–600) to 334 (149–874) m (P = 0·260, z = –1·13, r = 0·18). Fig. 4 shows the improvement by month during the study. Between-group comparisons were made using the Mann–Whitney U test. This showed a significant difference in median MWD at baseline between the HEP and www.bjs.co.uk
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600
600
500
500
Claudication distance (m)
Claudication distance (m)
764
400 300 200
HEP
NPW–
NPW+
HEP
b
Claudication distance – baseline
NPW–
NPW+
Claudication distance – 12 weeks 2000
Maximum walking distance (m)
2000 Maximum walking distance (m)
200
0
0
1500
1000
500
0 HEP
c
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100
a
400
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1000
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0
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Maximum walking distance – baseline
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d
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Maximum walking distance – 12 weeks
Comparisons of a,b claudication distance and c,d maximum walking distance between the groups at a,c baseline (0 weeks) and b,d 12 weeks. Median (horizontal line within box), i.q.r. (box), range (error bars), outliers (circles) and extreme outlier (asterisk) are shown. HEP, home exercise programme; NPW, nordic pole walking
Fig. 3
NPW+ groups (355 versus 389 m; U = 80·0, z = –2·94, P = 0·003, r = 0·49; large effect size). At 12 weeks, the differences were also significant between the control and NPW+ groups (334 versus 538 m; U = 76·5, z = –3·04, P = 0·002, r = 0·49; large effect size). There were, however, no significant differences between the HEP and NPW– groups at 12 weeks (334 and 400 m respectively; U = 136·5, z = –1·29, P = 0·199, r = 0·21; small effect size).
Ankle : brachial pressure index A paired-samples t test showed that the postexercise drop in ABPI was significantly less immediately in the NPW group when using poles than without (mean(s.d.) 0·18(0·17) versus 0·22(0·17); t (27) = 2·31, 2-tailed P = 0·029). The mean decrease in the postexercise drop in ABPI was 0·04 (95 per cent confidence interval (c.i.) 0·01 to 0·08). The η2 value of 0·17 indicated a large effect size. 2014 BJS Society Ltd Published by John Wiley & Sons Ltd
After 12 weeks the postexercise drop in ABPI was even less in the NPW group when using poles than without (0·13(0·10) versus 0·21(0·12); t (18) = 4·45, 2-tailed P < 0·001). The mean decrease in postexercise drop in ABPI after 12 weeks was 0·07 (95 per cent c.i. 0·04 to 0·10). The η2 value of 0·53 indicated a large effect size. There was no significant change in the postexercise ABPI in the HEP group. The mean percentage improvement in resting ABPI was greater in the NPW group than in the HEP control group (51 versus 23 per cent); this was not statistically significant (P = 0·183) but may be clinically relevant.
Calorific expenditure In the NPW group, a Wilcoxon signed rank test revealed a statistically significant increase in median calorific expenditure when using poles than not, both immediately (15 versus 7·5 kcal; P = 0·001, z = –3·19) and after 12 weeks www.bjs.co.uk
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Improvement in MWD (%)
200 HEP NPW– NPW+
150
100
50
0
–50
0
4
8
12
Week
Summary graph showing improvement in maximum walking distance (MWD) over 12 weeks. Error bars represent 95 per cent confidence intervals. HEP, home exercise programme; NPW, Nordic pole walking
Fig. 4
(19 versus 7·5 kcal; P < 0·001, z = –3·20), both with a large effect size (r = 0·52). There was no significant difference in calorific expenditure in the HEP group over 12 weeks (10 versus 9 kcal; P = 0·512, z = –0·66, r= 0·11).
Pain and perceived exertion As expected, patients’ perception of pain at their CD was similar between the groups, at both baseline and 12 weeks. At MWD, paired-samples t tests found no differences in perceived pain or exertion between groups, at either baseline or 12 weeks, despite the known 23 per cent increase in workload when Nordic poles are used (data not shown).
Compliance All patients in both groups recorded walking data in their diaries and used their pedometers to document the number of steps taken in each walk. Compliance was excellent in both groups as all participants completed more than the minimum of three walks per week. Discussion
This study demonstrated the benefits of NPW compared with a standard HEP in patients with intermittent claudication. Patients in the NPW group immediately walked further, to both CD and MWD, as in a previous study16 . CD and MWD continued to improve over the 12 weeks in all groups. The immediate increase in walking distance with poles is probably due to the decreased 2014 BJS Society Ltd Published by John Wiley & Sons Ltd
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level of leg pain caused by the reduction in leg loading stress12 . Using walking poles has been shown to allow individuals to walk faster with lower ground reaction forces18 . Collins and colleagues19 suggested that the longer stride when poles are used may give the calf muscles longer recovery time and allow more efficient use of the limited blood supply. The instant increase in MWD with poles may improve patient compliance, as the results are immediate and the psychological uplift is well documented15 . With standard exercise programmes it can take several weeks to feel any improvement20 . The fact that the NPW group walked further both with and without poles after 12 weeks could also be due to increased fitness21 . The control group also improved over the 12 weeks, but this improvement was not significant. This may have been because the patients in this group had a slightly higher rate of co-morbidities, which may have affected the results. The mean resting ABPI at baseline, however, was the same in both groups. In addition, many of the patients were recruited into the study at the start of the worst winter in years. A HEP requires patients to walk outside and this may have limited the duration of weekly exercise; patients using poles may have felt more confident. Although significant differences in MWD were found between the control and NPW+ groups, differences between the control and NPW– groups were not significant, even though the mean percentage improvement in MWD was greater in the NPW– group (50 versus 33 per cent). This was probably due to the small sample size of the groups after drop-out, mainly owing to illness, and the fact that weaker, non-parametric tests were necessary. The significant reduction in postexercise drop in ABPI in the NPW group when poles were used may be explained by the offloading effect of the poles19 . It could also be due to collateral vessel development. The mean percentage improvement in resting ABPI in the NPW group at 12 weeks was more than double that of the control group (51 versus 23 per cent), but this was not statistically significant. This again is probably due to the small sample size. Although this difference was not statistically significant, it may be clinically relevant and requires further investigation. As expected, calorific expenditure was significantly greater in the NPW+ group, owing to the increased workload22 , and the increase in stride length and walking speed18 . Despite this, pain and perceived exertion were similar in both groups, at baseline and 12 weeks, even though the NPW group walked significantly further. It www.bjs.co.uk
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is known that NPW works the body 23 per cent harder than normal walking11 , yet the participants scored their perceived exertion the same with, and without, poles. This suggests that they were unaware they were having to work harder. NPW could be an effective method of increasing cardiovascular fitness23 . Patients attended for exercise testing at 4-weekly intervals. This was to assist with compliance and identify any problems. The NPW+ group improved both immediately and from weeks 0 to 4. This was probably due to improved walking technique as the participants gained confidence in their poles. Walking distance in all groups plateaued slightly between weeks 4 and 8, and then the NPW group improved again at a higher rate than the control HEP group. The control group showed a steady but slow increase throughout. This suggests that a minimum 12-week programme is necessary, as suggested by previous exercise studies20 . The walking data in the diaries (including pedometer data) were analysed, but as there were so many extrinsic factors affecting walking distance, other than claudication pain (such as weather, time, illness), the data were not regarded as valuable. Walking speed (in kilometres per hour), calculated from the diary data, showed a tendency to increase in both groups during the 12 weeks. This may be relevant clinically, as a slow walking speed has been linked with reduced life expectancy24 . The main limitation of this study was the small sample size for analysis, owing to the number of patients who withdrew. The most common reason was ill health, which is a frequent problem in studies of elderly patients with peripheral arterial disease. Future studies should have a larger sample size. All patients in the NPW group kept their poles after the study, and many were keen to continue using them. It remains to be seen whether the results of a short exercise programme are durable. Acknowledgements
This study received financial support from the British Heart Foundation, the Private Physiotherapy Education Foundation and the Sheffield Vascular Institute. The authors thank Ardblair Sports, Blairgowrie (http://www.ardblairsports.com) for supplying the LekiTM Nordic poles and Omron (http://www.omron.co.uk) for the blood pressure monitors. They also thank K. Pyatt, L. Wilson and L. Walbridge at Steps Physiotherapy and Circulation Clinic, staff at the S10 gym and Sheffield University staff for all their hard work. Disclosure: The authors declare no conflict of interest. 2014 BJS Society Ltd Published by John Wiley & Sons Ltd
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14 Mikalacki M, Cokorilo N, Kati´c R. Effect of Nordic walking on functional ability and blood pressure in elderly women. Coll Antropol 2011; 35: 889–894. 15 Stoughton L. Psychological Profiles Before and After 12 Weeks of Walking or Exerstrider Training in Adult Women (MSc Thesis). University of Wisconsin La-Crosse: La Crosse, 1992. 16 Oakley C, Zwierska I, Tew G, Beard JD, Saxton JM. Nordic poles immediately improve walking distance in patients with intermittent claudication. Eur J Vasc Endovasc Surg 2008; 36: 689–694. 17 Wind J, Koelemay MJ. Exercise therapy and the additional effect of supervision on exercise therapy in patients with intermittent claudication. Systematic review of randomised controlled trials. Eur J Vasc Endovasc Surg 2007; 34: 689–694. 18 Willson J, Torry MR, Decker MJ, Kernozek T, Steadman JR. Effects of walking poles on lower extremity gait mechanics. Med Sci Sports Ex 2001; 33: 142–147. 19 Collins EG, Edwin Langbein W, Orebaugh C, Bammert C, Hanson K, Reda D et al. Polestriding exercise and vitamin E
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Snapshot quiz
Snapshot quiz 14/8 Answer: The anal abscess was due an Enterobius vermicularis infestation. Numerous live threadworms were found at the dentate line within the anal crypts and in the lower rectum. The intersphincteric abscess was drained and three threadworms were found in the cavity. Mixed colonic organisms were cultured; the abscess space was laid open, and the child was treated with an anthelmintic agent (pyrantel). He made an uncomplicated recovery. E vermicularis infestation normally involves the caecum, appendix and ileum. Perianal abscesses due to E. vermicularis are rare, and it is supposed that they are because of worms passing into an anal gland. Intraoperative view of the anal and perianal region before drainage of the abscess, showing live threadworms (Enterobius vermicularis). This video can be viewed in the Clinical Media Library on the BJS website (www.bjs.co.uk).
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BJS 2014; 101: 760–767
Randomized clinical trial comparing Nordic pole walking and a standard home exercise programme in patients with intermittent claudication C. Spafford1 , C. Oakley1 and J. D. Beard2 1 Sheffield Nordic Walking Research, Steps Physiotherapy and Circulation Clinics, and 2 Sheffield Vascular Institute, Northern General Hospital, Sheffield, UK Correspondence to: Mrs C. Spafford, Steps Physiotherapy and Circulation Clinics, 32 Southbourne Road, Sheffield S10 2QN, UK (e-mail: [email protected])
Background: This was a randomized clinical trial to determine whether Nordic pole walking (NPW)
is more effective in improving walking distance than a standard home exercise programme (HEP) in patients with intermittent claudication. Methods: Fifty-two patients with stable claudication were allocated randomly to a standard HEP or NPW group, and asked to complete three 30-min walks per week for 12 weeks. Claudication distance (CD) and maximum walking distance (MWD) were measured at 0 (baseline), 4, 8 and 12 weeks. Patients in the NPW group were tested with (NPW+) and without (NPW–) poles. Results: For NPW+, CD increased immediately from a median (range) of 124 (71–248) m to 148 (116–426) m, and MWD from 248 (149–900) to 389 (194–1099) m (P = 0·004 and P < 0·001 respectively). By 12 weeks, CD had further increased to 199 (118–550) m and MWD had more than doubled to 538 (250–1750) m (P < 0·001 and P = 0·001). For NPW–, CD at 12 weeks had increased significantly to 151 (100–328) m and MWD to 400 (200–900) m (P < 0·001 and P = 0·006 respectively). At 12 weeks the changes in the standard HEP group were not significant, despite excellent compliance: CD from 107 (56–332) to 153 (59–321) m and MWD from 355 (92–600) to 334 (149–874) m (P = 0·030 and P = 0·260 respectively). Conclusion: A 12-week exercise programme using Nordic poles significantly improved walking distance in claudicants compared with a standard HEP. Registration number: ISRCTN78168304 (http://www.controlled-trials.com). Presented to a meeting of the Vascular Society of Great Britain and Ireland, Manchester, UK, November 2013 Paper accepted 26 February 2014 Published online 24 April 2014 in Wiley Online Library (www.bjs.co.uk). DOI: 10.1002/bjs.9519
Introduction
Peripheral arterial disease can limit blood flow to the legs on walking, causing intermittent claudication. The limited exercise capacity of these patients increases their risk of obesity and reduces cardiovascular fitness, which in turn increases their susceptibility to co-morbidities such as diabetes and cardiac disease1 . Walking advice alone is ineffective, as patients with claudication are usually non-compliant owing to a lack of support and motivation2 . Exercise therapy is less costly and carries a lower risk than radiological or surgical intervention. The proven benefits of exercise include improvement in walking distance, cardiovascular fitness, quality of life and life expectancy3 . 2014 BJS Society Ltd Published by John Wiley & Sons Ltd
Supervised exercise programmes have been found to be as effective as angioplasty4 , but are expensive to run and compliance may be as low as 34 per cent5 . Home exercise programmes (HEPs) are less expensive, and integrate more readily into the patient’s lifestyle6 , but there is a lack of quality evidence of the efficacy of HEPs compared with supervised exercise programmes. The greatest benefits are seen when patients exercise for a minimum of three times a week for 30 min, and walk to maximal pain levels7 . Unsupervised, but supported, exercise programmes in the community may be a good compromise in terms of both cost and compliance8 . Support in the form of telephone or online coaching and problem-solving, plus walking diaries and pedometers, may be the best way to increase patient BJS 2014; 101: 760–767
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reproducibility and reliability, and is more suitable for evaluating walking distance in patients with intermittent claudication17 . The primary aim of this study was to determine whether NPW was more effective in improving walking distance than a standard, supported HEP. The secondary aims were to compare calorific expenditure as a measure of cardiac workload, postexercise ABPI and compliance. Methods
Fig. 1
Nordic walking poles
compliance with exercise programmes6,9,10 . However, unlike revascularization, all current exercise programmes suffer from a lack of immediate benefit. Nordic pole walking (NPW) is an accepted form of exercise training for athletes (Fig. 1). NPW results in an increase in oxygen use (23 per cent) and calorific expenditure (22 per cent) compared with regular walking, without an increase in perceived exertion11 . NPW involves a significant contribution from the arm and shoulder muscles, which aid forward propulsion. It also reduces the load on the spine and legs when walking uphill or on the flat compared with ordinary walking12 . This may be an additional benefit as many patients with claudication also have arthritis of the spine, hips and knees. There is evidence that NPW improves cardiovascular fitness in many patient groups, including those with claudication13 , and is a suitable form of exercise for the older population14 . Nordic walking feels easier than normal walking, but works the cardiovascular system 23 per cent harder, as all muscles are used. There is also known psychological mood enhancement attributed to NPW15 . A pilot study by Oakley and colleagues16 in patients with intermittent claudication showed that NPW immediately increased walking distance on a treadmill, decreased leg pain, increased cardiovascular effort, and was perceived as being easier than normal walking. The study also showed that NPW caused a lower reduction in the postexercise ankle : brachial pressure index (ABPI), suggesting some offloading of the leg muscles. Most studies examining the effects of exercise in patients with peripheral arterial disease use a treadmill. Measuring walking distance on a treadmill is an accepted standard, but bears little similarity to the exercise patients experience in their daily lives. It has been suggested that the shuttle walking test is more representative, shows better interstudy 2014 BJS Society Ltd Published by John Wiley & Sons Ltd
The study was approved by the National Research Ethics Service Yorkshire and the Humber–South Yorkshire Ethics Committee (reference no. 11/YH/0100; protocol no. STH15454). The research study is listed in the UKCRN Portfolio database (reference 10781) and also registered with the ISRCTN Register (http://www. controlled-trials.com/ISRCTN78168304). Consecutive patients with stable claudication were referred from local vascular clinics over 12 months. A full medical history was taken and clinical assessment was carried out for each patient before enrolment in the study and documented on a pro forma, along with the demographic details. Patients were invited to attend a clinic appointment with a research physiotherapist, where the study was discussed in full, and informed consent was obtained. Height and weight were recorded, and patients were taught the technique of NPW. Each patient was then allocated randomly to either NPW or HEP (control group), using the fish bowl method, and given appointments to attend gym sessions for tests at 0, 4, 8 and 12 weeks. After the initial appointment, patients were given instructions on exercising at home. Patients in the NPW group were given a pair of LEKI (http://www.leki.co.uk) Nordic walking poles adjusted for height (height × 0·7) and asked to walk using the poles for at least 30 min three times per week. The HEP group was given written instructions to walk at their normal pace for at least 30 min three times per week. Both groups were given a pedometer (Yamaxx Digiwalker CW-700/701; http://www.yamaxx.com), and a diary to record the date, time and duration of each period of exercise, together with the pedometer reading (number of steps taken) and perceived exertion. Patients were shown (and given written instructions on) how to use the pedometers. They were supported by a weekly telephone call from one of the research physiotherapists. Diary entries and activity data were recorded when they attended the gym sessions. Patients’ diaries were monitored to determine whether any changes in walking distance were due to non-compliance. www.bjs.co.uk
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Enrolment
Referred from clinic n = 86 Excluded n = 25 Did not meet inclusion criteria n = 2 Declined to participate n = 23 Consented n = 61
Analysis
Follow-up
Allocation
Randomized n = 52
Fig. 2
Withdrawn after consent, before commencing study n = 9 Cancer n = 2 Cardiac n = 1 Back pain n = 1 Respiratory n = 1 General health deteriorated n = 1 Having surgery n = 1 No time n = 2
Allocated to home exercise programme n = 24
Allocated to Nordic pole walking n = 28
Withdrawn during study n = 5 Died (MI) n = 1 Had surgery n = 1 Ill health n = 1 No time n = 2
Withdrawn during study n = 9 Too good with poles n = 2 Ill health n = 2 No time n = 5
Analysed n = 19
Analysed n = 19
CONSORT diagram for the trial. MI, myocardial infarction
At each test session body mass index was calculated. Resting ABPI was taken before exercising using a hand-held Doppler. Blood pressure and heart rate were recorded at rest. Patients were fitted with a heart monitor chest belt (Suunto M2; Suunto, Vantaa, Finland) for each test. A modified shuttle walking test, consisting of walking a 50-m figure-of-eight circuit as fast as possible and for as long as possible, was then performed. The HEP group completed the test once, without poles. The NPW group did the test twice, once with poles (NPW+) and once without poles (NPW–), with a rest in between while their heart rate and blood pressure returned to normal. The order of the tests was allocated randomly at each visit, using the fish bowl method, to avoid bias. During each test, the following data were collected: claudication distance (CD) in metres, CD time (using a stopwatch), CD heart rate, maximum walking distance (MWD) in metres, MWD time, MWD heart rate, average heart rate, calorific expenditure, and rating of perceived exertion and pain (using Borg’s CR-10 scale). Time and distance were used to calculate walking speed in metres 2014 BJS Society Ltd Published by John Wiley & Sons Ltd
per second. ABPI, blood pressure and heart rate were measured immediately after exercise, then blood pressure and heart rate were retested every 5 min until the preexercise levels were reached. These tests were performed at 0 (baseline), 4, 8 and 12 weeks. The difference in distance walked with and without poles at the baseline assessment represented the immediate improvement in the NPW group.
Inclusion and exclusion criteria Included patients had stable intermittent claudication for at least 6 months, and a resting ABPI below 0·9. They were unsuitable for revascularization and/or had no revascularization procedure in the previous 6 months. The level of disease and unsuitability for revascularization had been determined previously by duplex ultrasound examination and/or magnetic resonance arteriography. Patients were excluded if they had other conditions that could limit their walking distance (such as breathlessness or severe osteoarthrosis). www.bjs.co.uk
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Table 1
Demographics of the patient cohort
Age (years)* Sex ratio (M : F) Body mass index (kg/m2 )* Level of PAD Calf Thigh Buttock Resting ABPI* Smoking status Current smoker Previous smoker Never smoked Antihypertensive medication Beta-blockers Previous operation COPD Ischaemic heart disease Previous stroke Diabetes Arthritis Statins Antiplatelet agents Warfarin
Total (n = 52)
Home exercise programme (n = 24)
Nordic pole walking (n = 28)
65(2) (39–84) 35 : 17 28(1)
65(2) 16 : 8 29(1)
65(2) 19 : 9 28(1)
49 (94) 2 (4) 1 (2) 0·61(0·03)
21 (88) 2 (8) 1 (4) 0·61(0·04)
28 (100) 0 (0) 0 (0) 0·61(0·03)
9 (17) 31 (60) 12 (23) 31 (60) 7 (13) 11 (21) 8 (15) 11 (21) 2 (4) 16 (31) 7 (13) 47 (90) 43 (83) 2 (4)
5 (21) 15 (63) 4 (17) 16 (67) 4 (17) 5 (21) 4 (17) 5 (21) 2 (8) 9 (38) 4 (17) 21 (88) 20 (83) 0 (0)
4 (14) 16 (57) 8 (29) 15 (54) 3 (11) 6 (21) 4 (14) 6 (21) 0 (0) 7 (25) 3 (11) 26 (93) 23 (82) 2 (7)
Values in parentheses are percentages unless indicated otherwise; *values are mean(s.e.m.) (range). Ankle : brachial pressure index (ABPI) data are presented for the most symptomatic leg. PAD, peripheral arterial disease; COPD, chronic obstructive pulmonary disease.
Statistical analysis There was no previous single study from which all the variables needed to perform an accurate power calculation could be obtained. The variables were therefore estimated by combining the results of previous studies, with MWD as the primary outcome. It was estimated that a sample size of 42 participants would provide 80 per cent power with an α value of 0·05 and an anticipated effect size of 0·8 (Cohen’s d). This sample size was increased to 50 to allow for a drop-out rate of 20 per cent (the usual rate for many claudication studies). Descriptive statistics were obtained and tested for normal distribution using the Kolmogorov–Smirnov test. The walking distance data (MWD and CD) violated the assumption of normality and could not be normalized using data transformation techniques, so non-parametric tests were used. The Wilcoxon signed rank test was used to analyse differences in walking distance and, as multiple comparisons were being made, the α level was set to P < 0·017 using a Bonferroni correction to reduce the risk of type I errors. Differences between groups were analysed using the Mann–Whitney U test. Differences 2014 BJS Society Ltd Published by John Wiley & Sons Ltd
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in calorific expenditure and resting ABPI were assessed using the Wilcoxon signed rank and paired-samples t tests respectively. Data were analysed using SPSS version 20 (IBM, Armonk, New York, USA). Results
Eighty-six patients with stable claudication, aged 39–84 years, were referred for assessment. Following referral, 25 patients were excluded from the study or declined to participate owing to travelling distance or time constraints. A further nine withdrew after consent but before commencing the walking (Fig. 2). Fifty-two patients were randomized (28 NPW, 24 HEP). Baseline characteristics were well balanced between the two groups (Table 1). After commencing the walking, a further 14 patients discontinued the study: nine in the NPW group and five in the HEP group (2 had more proximal disease). Two patients in the NPW group were withdrawn, as they failed to reach CD and MWD when using the poles on initial testing, and were therefore deemed too good for this study. In the HEP group, one patient died from myocardial infarction, but this was not while exercising. A total of 19 patients in each group remained for analysis.
Walking distance The primary outcome measure was walking distance: CD and MWD. The NPW group increased their CD immediately from a median (range) of 124 (71–248) m without poles (NPW–) to 148 (116–426) m with poles (NPW+) (P = 0·004, z = –2·90, r = 0·47), and MWD increased from 248 (149–900) to 389 (194–1099) m respectively (P < 0·001, z = –3·55, r = 0·58). At 12 weeks with poles (NPW+), CD had increased to 199 (118–550) m (P < 0·001, z = –3·58, r= 0·58), and MWD had more than doubled to 538 (250–1750) m (P = 0·001, z = –3·34, r = 0·54). Without poles (NPW–), CD had increased significantly at 12 weeks to 151 (100–328) m (P < 0·001, z = –3·78, r = 0·61) and MWD to 400 (200–900) m (P = 0·006, z = –2·77, r = 0·45) (Fig. 3). At 12 weeks, increases in the standard HEP group were not significant, despite excellent compliance; CD changed from 107 (56–332) to 153 (59–321) m (P = 0·030 (not significant with Bonferroni correction), z = –2·17, r = 0·35) and MWD from 355 (92–600) to 334 (149–874) m (P = 0·260, z = –1·13, r = 0·18). Fig. 4 shows the improvement by month during the study. Between-group comparisons were made using the Mann–Whitney U test. This showed a significant difference in median MWD at baseline between the HEP and www.bjs.co.uk
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600
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Claudication distance (m)
Claudication distance (m)
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400 300 200
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b
Claudication distance – baseline
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Claudication distance – 12 weeks 2000
Maximum walking distance (m)
2000 Maximum walking distance (m)
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c
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Comparisons of a,b claudication distance and c,d maximum walking distance between the groups at a,c baseline (0 weeks) and b,d 12 weeks. Median (horizontal line within box), i.q.r. (box), range (error bars), outliers (circles) and extreme outlier (asterisk) are shown. HEP, home exercise programme; NPW, nordic pole walking
Fig. 3
NPW+ groups (355 versus 389 m; U = 80·0, z = –2·94, P = 0·003, r = 0·49; large effect size). At 12 weeks, the differences were also significant between the control and NPW+ groups (334 versus 538 m; U = 76·5, z = –3·04, P = 0·002, r = 0·49; large effect size). There were, however, no significant differences between the HEP and NPW– groups at 12 weeks (334 and 400 m respectively; U = 136·5, z = –1·29, P = 0·199, r = 0·21; small effect size).
Ankle : brachial pressure index A paired-samples t test showed that the postexercise drop in ABPI was significantly less immediately in the NPW group when using poles than without (mean(s.d.) 0·18(0·17) versus 0·22(0·17); t (27) = 2·31, 2-tailed P = 0·029). The mean decrease in the postexercise drop in ABPI was 0·04 (95 per cent confidence interval (c.i.) 0·01 to 0·08). The η2 value of 0·17 indicated a large effect size. 2014 BJS Society Ltd Published by John Wiley & Sons Ltd
After 12 weeks the postexercise drop in ABPI was even less in the NPW group when using poles than without (0·13(0·10) versus 0·21(0·12); t (18) = 4·45, 2-tailed P < 0·001). The mean decrease in postexercise drop in ABPI after 12 weeks was 0·07 (95 per cent c.i. 0·04 to 0·10). The η2 value of 0·53 indicated a large effect size. There was no significant change in the postexercise ABPI in the HEP group. The mean percentage improvement in resting ABPI was greater in the NPW group than in the HEP control group (51 versus 23 per cent); this was not statistically significant (P = 0·183) but may be clinically relevant.
Calorific expenditure In the NPW group, a Wilcoxon signed rank test revealed a statistically significant increase in median calorific expenditure when using poles than not, both immediately (15 versus 7·5 kcal; P = 0·001, z = –3·19) and after 12 weeks www.bjs.co.uk
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Improvement in MWD (%)
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–50
0
4
8
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Summary graph showing improvement in maximum walking distance (MWD) over 12 weeks. Error bars represent 95 per cent confidence intervals. HEP, home exercise programme; NPW, Nordic pole walking
Fig. 4
(19 versus 7·5 kcal; P < 0·001, z = –3·20), both with a large effect size (r = 0·52). There was no significant difference in calorific expenditure in the HEP group over 12 weeks (10 versus 9 kcal; P = 0·512, z = –0·66, r= 0·11).
Pain and perceived exertion As expected, patients’ perception of pain at their CD was similar between the groups, at both baseline and 12 weeks. At MWD, paired-samples t tests found no differences in perceived pain or exertion between groups, at either baseline or 12 weeks, despite the known 23 per cent increase in workload when Nordic poles are used (data not shown).
Compliance All patients in both groups recorded walking data in their diaries and used their pedometers to document the number of steps taken in each walk. Compliance was excellent in both groups as all participants completed more than the minimum of three walks per week. Discussion
This study demonstrated the benefits of NPW compared with a standard HEP in patients with intermittent claudication. Patients in the NPW group immediately walked further, to both CD and MWD, as in a previous study16 . CD and MWD continued to improve over the 12 weeks in all groups. The immediate increase in walking distance with poles is probably due to the decreased 2014 BJS Society Ltd Published by John Wiley & Sons Ltd
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level of leg pain caused by the reduction in leg loading stress12 . Using walking poles has been shown to allow individuals to walk faster with lower ground reaction forces18 . Collins and colleagues19 suggested that the longer stride when poles are used may give the calf muscles longer recovery time and allow more efficient use of the limited blood supply. The instant increase in MWD with poles may improve patient compliance, as the results are immediate and the psychological uplift is well documented15 . With standard exercise programmes it can take several weeks to feel any improvement20 . The fact that the NPW group walked further both with and without poles after 12 weeks could also be due to increased fitness21 . The control group also improved over the 12 weeks, but this improvement was not significant. This may have been because the patients in this group had a slightly higher rate of co-morbidities, which may have affected the results. The mean resting ABPI at baseline, however, was the same in both groups. In addition, many of the patients were recruited into the study at the start of the worst winter in years. A HEP requires patients to walk outside and this may have limited the duration of weekly exercise; patients using poles may have felt more confident. Although significant differences in MWD were found between the control and NPW+ groups, differences between the control and NPW– groups were not significant, even though the mean percentage improvement in MWD was greater in the NPW– group (50 versus 33 per cent). This was probably due to the small sample size of the groups after drop-out, mainly owing to illness, and the fact that weaker, non-parametric tests were necessary. The significant reduction in postexercise drop in ABPI in the NPW group when poles were used may be explained by the offloading effect of the poles19 . It could also be due to collateral vessel development. The mean percentage improvement in resting ABPI in the NPW group at 12 weeks was more than double that of the control group (51 versus 23 per cent), but this was not statistically significant. This again is probably due to the small sample size. Although this difference was not statistically significant, it may be clinically relevant and requires further investigation. As expected, calorific expenditure was significantly greater in the NPW+ group, owing to the increased workload22 , and the increase in stride length and walking speed18 . Despite this, pain and perceived exertion were similar in both groups, at baseline and 12 weeks, even though the NPW group walked significantly further. It www.bjs.co.uk
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is known that NPW works the body 23 per cent harder than normal walking11 , yet the participants scored their perceived exertion the same with, and without, poles. This suggests that they were unaware they were having to work harder. NPW could be an effective method of increasing cardiovascular fitness23 . Patients attended for exercise testing at 4-weekly intervals. This was to assist with compliance and identify any problems. The NPW+ group improved both immediately and from weeks 0 to 4. This was probably due to improved walking technique as the participants gained confidence in their poles. Walking distance in all groups plateaued slightly between weeks 4 and 8, and then the NPW group improved again at a higher rate than the control HEP group. The control group showed a steady but slow increase throughout. This suggests that a minimum 12-week programme is necessary, as suggested by previous exercise studies20 . The walking data in the diaries (including pedometer data) were analysed, but as there were so many extrinsic factors affecting walking distance, other than claudication pain (such as weather, time, illness), the data were not regarded as valuable. Walking speed (in kilometres per hour), calculated from the diary data, showed a tendency to increase in both groups during the 12 weeks. This may be relevant clinically, as a slow walking speed has been linked with reduced life expectancy24 . The main limitation of this study was the small sample size for analysis, owing to the number of patients who withdrew. The most common reason was ill health, which is a frequent problem in studies of elderly patients with peripheral arterial disease. Future studies should have a larger sample size. All patients in the NPW group kept their poles after the study, and many were keen to continue using them. It remains to be seen whether the results of a short exercise programme are durable. Acknowledgements
This study received financial support from the British Heart Foundation, the Private Physiotherapy Education Foundation and the Sheffield Vascular Institute. The authors thank Ardblair Sports, Blairgowrie (http://www.ardblairsports.com) for supplying the LekiTM Nordic poles and Omron (http://www.omron.co.uk) for the blood pressure monitors. They also thank K. Pyatt, L. Wilson and L. Walbridge at Steps Physiotherapy and Circulation Clinic, staff at the S10 gym and Sheffield University staff for all their hard work. Disclosure: The authors declare no conflict of interest. 2014 BJS Society Ltd Published by John Wiley & Sons Ltd
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References 1 Zeymer U, Parhofer KG, Pittrow D, Binz C, Schwertfeger M, Limbourg T et al. Risk factor profile, management and prognosis of patients with peripheral arterial disease with or without coronary artery disease: results of the prospective German REACH registry cohort. Clin Res Cardiology 2009; 98: 249–256. 2 Cheetham DR, Burgess L, Ellis M, Williams A, Greenhalgh RM, Davies AH. Does supervised exercise offer adjuvant benefit over exercise advice alone for the treatment of intermittent claudication? A randomised trial. Eur J Vasc Endovasc Surg 2004; 27: 17–23. 3 Casillas JM, Troisgros O, Hannequin A, Gremeaux V, Ader P, Rapin A et al. Rehabilitation in patients with peripheral arterial disease. Ann Phys Rehab Med 2011; 54: 443–461. 4 Mazari FA, Khan JA, Carradice D, Samuel N, Abdul Rahman MN, Gulati S et al. Randomized clinical trial of percutaneous transluminal angioplasty, supervised exercise and combined treatment for intermittent claudication due to femoropopliteal arterial disease. Br J Surg 2012; 99: 39–48. 5 Gardner AW, Parker DE, Montgomery PS, Scott KJ, Blevins SM. Efficacy of quantified home-based exercise and supervised exercise in patients with intermittent claudication: a randomized controlled trial. Circulation 2011; 123: 491–498. 6 Fakhry F, Spronk S, de Ridder M, den Hoed PT, Hunink MG. Long-term effects of structured home-based exercise program on functional capacity and quality of life in patients with intermittent claudication. Arch Phys Med Rehab 2011; 92: 1066–1073. 7 Ratliff DA, Puttick M, Libertiny G, Hicks RCJ, Earby LE, Richards T. Supervised exercise training for intermittent claudication: lasting benefit at three years. Eur J Vasc Endovasc Surg 2007; 34: 322–326. 8 Roberts AJ, Roberts EB, Sykes K, De Cossart L, Edwards P, Cotterrell D. Physiological and functional impact of an unsupervised but supported exercise programme for claudicants. Eur J Vasc Endovasc Surg 2008; 36: 319–324. 9 Bravata DM, Smith-Spangler C, Sundaram V, Gienger AL, Lin N, Lewis R et al. Using pedometers to increase physical activity and improve health – a systematic review. JAMA 2007; 298: 2296–2304. 10 Makris GC, Lattimer CR, Lavida A, Geroulakos G. Availability of supervised exercise programs and the role of structured home-based exercise in peripheral arterial disease. Eur J Vasc Endovasc Surg 2012; 44: 569–575. 11 Church TS, Earnest CP, Morss GM. Field testing of physiological responses associated with Nordic Walking. Res Q Exerc Sport 2002; 73: 296–300. 12 Koizumi T, Tsujiuchi N, Takeda M, Fujikura R, Kojima T. Load dynamics of joints in Nordic walking. Procedia Engineering 2011; 13: 544–551. 13 Langbein WE, Collins EG, Orebaugh C, Maloney C, Williams KJ, Littooy FN et al. Increasing exercise tolerance of persons limited by claudication pain using polestriding. J Vasc Surg 2002; 35: 887–893.
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14 Mikalacki M, Cokorilo N, Kati´c R. Effect of Nordic walking on functional ability and blood pressure in elderly women. Coll Antropol 2011; 35: 889–894. 15 Stoughton L. Psychological Profiles Before and After 12 Weeks of Walking or Exerstrider Training in Adult Women (MSc Thesis). University of Wisconsin La-Crosse: La Crosse, 1992. 16 Oakley C, Zwierska I, Tew G, Beard JD, Saxton JM. Nordic poles immediately improve walking distance in patients with intermittent claudication. Eur J Vasc Endovasc Surg 2008; 36: 689–694. 17 Wind J, Koelemay MJ. Exercise therapy and the additional effect of supervision on exercise therapy in patients with intermittent claudication. Systematic review of randomised controlled trials. Eur J Vasc Endovasc Surg 2007; 34: 689–694. 18 Willson J, Torry MR, Decker MJ, Kernozek T, Steadman JR. Effects of walking poles on lower extremity gait mechanics. Med Sci Sports Ex 2001; 33: 142–147. 19 Collins EG, Edwin Langbein W, Orebaugh C, Bammert C, Hanson K, Reda D et al. Polestriding exercise and vitamin E
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Snapshot quiz
Snapshot quiz 14/8 Answer: The anal abscess was due an Enterobius vermicularis infestation. Numerous live threadworms were found at the dentate line within the anal crypts and in the lower rectum. The intersphincteric abscess was drained and three threadworms were found in the cavity. Mixed colonic organisms were cultured; the abscess space was laid open, and the child was treated with an anthelmintic agent (pyrantel). He made an uncomplicated recovery. E vermicularis infestation normally involves the caecum, appendix and ileum. Perianal abscesses due to E. vermicularis are rare, and it is supposed that they are because of worms passing into an anal gland. Intraoperative view of the anal and perianal region before drainage of the abscess, showing live threadworms (Enterobius vermicularis). This video can be viewed in the Clinical Media Library on the BJS website (www.bjs.co.uk).
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