Protocols Effect of backward walking treadmill training on walking capacity after stroke: a randomized clinical trial Stella Maris Michaelsen1*, Angélica Cristiane Ovando2, Fernanda Romaguera1, and Louise Ada3 Rationale Residual walking deficits are common in people after stroke. Treadmill training can increase walking speed and walking distance. A new way to increase the challenge of walking is to walk backwards. Backward treadmill walking may provide advantages by promoting improvement in balance, walking spatiotemporal parameters and quality that may reflect in improving walking distance. Aim This study will test the hypothesis that backward treadmill walking is superior to forward treadmill walking in improving walking capacity, walking parameters, quality and balance in people with stroke. Design A prospective, single-blinded, randomized trial will randomly allocate 88 community-dwelling people after stroke into either an experimental or control group. The experimental group will undertake 30-min sessions of backward treadmill walking, three-days/week for six-weeks, while the control group will undertake the same dose of forward treadmill walking. Training will begin at the baseline overground walking speed and will increase each week by 10% of baseline speed. Study outcomes The primary outcome will be distance walked in the 6-min Walk Test. Secondary outcomes will be walking speed, step length, cadence, and one-leg stance time. Outcomes will be collected by a researcher blinded to group allocation at baseline (Week 0), at the end of training period (Week 6), and three-months after the cessation of intervention (Week 18). Discussion If backward treadmill walking can improve walking capacity more than forward treadmill training in stroke, it may have broader implications because walking capacity has been shown to predict physical activity level and community participation. Key words: ambulation, clinical trial, intervention, rehabilitation, stroke
Correspondence: Stella Maris Michaelsen*, Department of Physical Therapy – Centro de Ciências da Saúde e do Esporte, Universidade do Estado de Santa Catarina, Rua Pascoal Simone, 358 – Coqueiros, 88080-350, Florianópolis, SC, Brazil. E-mail: [email protected]
1 Department of Physical Therapy, Physical Therapy Master Program, Universidade do Estado de Santa Catarina, Florianópolis, Santa Catarina, Brazil 2 Department of Physical Therapy, Universidade do Estado de Santa Catarina, Florianópolis, Santa Catarina, Brazil 3 Discipline of Physiotherapy, The University of Sydney, Lidcombe, New South Wales, Australia Received: 30 August 2013; Accepted: 16 December 2013; Published online 15 April 2014 Conflict of interest: The authors declare that there is no conflict of interest. Funding: The trial is funded by the Brazilian National funding agency (Conselho Nacional de Pesquisa). DOI: 10.1111/ijs.12255 © 2014 The Authors. International Journal of Stroke © 2014 World Stroke Organization
Introduction and rationale Walking is one of the most important activities to enable community participation. After stroke, although the majority of patients recover independent walking, many have residual walking disabilities. Many individuals after stroke cannot walk fast or far enough, which reduces their ability to walk outside the house. Even for those undergoing inpatient rehabilitation, walking quality can be surprisingly poor at the time of discharge from hospital, with one study finding that only 7% of people after stroke are able to have independent community ambulation at discharge of rehabilitation (1) and mobility problems persist in the chronic phase after stroke (2). The walking speed of community-dwelling people after stroke has been reported to be 40% less, and six-minute walking distance about half the value expected in age- and gender-matched people (3). This reduced capacity to walk long distances can restrict the access for community exercise programs as well as result in major limitations in community participation. The treadmill is frequently used for walking training in people after stroke. It allows a controlled speed and an intensive amount of practice (4), working as a ‘forced use’ (5). A recent review on treadmill training (6) suggests that treadmill training can increase walking speed by 0·12 m/s and improve walking distance by 40 m. A relatively new way to increase the challenge of walking is to walk backwards. At a given speed, when compared with forward walking, backward walking elicits more electromyographic activity which in turn results in higher physiological cost and greater perceived exertion (7–9). Hip extension is more active in backward walking due to the concentric contraction of knee flexors during early swing phase (10,11) which may be beneficial at improving lower limb coordination after stroke. Also, backward walking is more difficult and demanding than forward walking due to its postural instability and may therefore provide a training challenge to balance (12). There have been three clinical trials of backward walking. One trial (13) in chronic stroke found that backward overgound walking increased walking speed while another trial (14) found that backward treadmill walking also increased speed compared with overground walking. The only trial to compare backward treadmill walking with forward treadmill walking (15) was carried out in acute just-ambulatory patients and was therefore performed with body weight support, but it found that backward walking produced more independent walking. The main objectives of this trial are: to determine whether six-weeks of backward treadmill walking is more effective than six-weeks of forward treadmill walking in improving walking capacity, walking parameters, walking quality, and balance in Vol 9, June 2014, 529–532
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community-dwelling people after stroke. We hypothesize that backward treadmill walking will lead to a greater increase in walking capacity compared with forward treadmill walking.
Method Design A prospective, randomized trial with concealed randomization, blinded assessment, and intention-to-treat analysis will be carried out (Fig. 1). Community-dwelling people with stroke will be recruited and randomly allocated into either a backward treadmill walking (experimental group) or a forward treadmill walking (control group). Both groups will undertake 30 min of treadmill (backward or forward) walking plus 10 min forward overground walking, three times per week for six-weeks. Outcome measures will be collected by a trained researcher at baseline (Week 0), at the end of training period (Week 6), and three-months after the cessation of intervention (Week 18). Both data collection and data analysis will be completed by a researcher who is blinded to group allocation. The study has obtained ethical approval from the appropriate Human Research Ethics Committees. The trial is registered at the Brazilian Clinical Trials Registry (REBEC). Patient population – inclusion and exclusion criteria People with stroke living in the community will be eligible if they are:
• >6 < 18 months after their first stroke (diagnosis of stroke will be assured by CT scan) • community-dwelling and have been discharged from formal rehabilitation • capable of providing consent (Mini Mental State Exam score > 23) • older than 20 years of age, and • able to independently walk 10 m without walking aids >0·4 < 1·2 m/s They will be excluded if they have: • unstable cardiac status which would preclude participation in a moderate exercise program • severe cognitive deficits and/or language problems which might prevent them from following instructions during the data collection and/or interventions, and • adverse health conditions which might affect their walking capacity (e.g., vestibular disturbances, severe arthritis, or other neurological disorders). Randomization Randomisation will be computer generated, independent, and concealed. Participants will be recruited in cohorts of 8. Each cohort will be ranked in descending order according to comfortable walking speed and then organized into matched pairs. The participants in each pair will then be randomly assigned (com-
Eligibility confirmed Informed Consent obtained
Pre-intervention (Week 0) Initial measurements – characterization of the participants Measurements Primary outcomes Walking capacity: distance in meters (6MWT) Secondary outcomes Balance: time balancing one leg (s) - paretic and non-paretic Spatiotemporal parameters: speed (m/s), step length (m), cadence (steps/min), Walking quality: kinematics
Randomization 88 randomized participants 30 min backward treadmill walking + 10 min overground walking 3 x week (44 participants)
Post-intervention (Week 6) Measurements Primary outcomes Walking capacity: distance in meters (6MWT) Secondary outcomes Balance: time balancing one leg (s) - paretic and non-paretic Spatiotemporal parameters: speed (m/s), step length (m), cadence (steps/min), Walking quality: kinematics
30 min forward treadmill walking + 10 min overground walking 3 x week (44 participants)
12 weeks from cessation of intervention (Week 18) Primary outcomes Walking capacity: distance in meters (6MWT) Secondary outcomes Balance: time balancing one leg (s) - paretic and non-paretic Spatiotemporal parameters: speed (m/s), step length (m), cadence (steps/min), Walking quality: kinematics
Fig. 1 Flow diagram of the planned trial pathway.
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© 2014 The Authors. International Journal of Stroke © 2014 World Stroke Organization
S. M. Michaelsen et al. puter generated) to the experimental or control group by an independent researcher (concealed). Intervention Experimental intervention will receive 18 sessions, each consisting of 30 min of backward treadmill walking and 10 min of forward overground walking, three times a week, for six-weeks. The control group will receive 18 sessions, each consisting of 30 min of forward treadmill walking and 10 min of forward overground walking. Treadmill training for both groups will begin at baseline overground walking speed (backward or forward) and will increase weekly by 10% of baseline speed. The program will be carried out in a community setting. Information describing the specific features of the training session (such as treadmill speed, distance walked, etc) will be recorded to monitor adherence to the protocol and to be able to describe the intervention accurately. Primary outcome Walking capacity will be measured as distance (m) covered in six-minutes (i.e., 6-min Walk Test). Using a standardized protocol (16), participants will be instructed to cover the maximum distance possible in six-minutes, using aids and taking rests as needed. Secondary outcomes Secondary outcomes will be walking parameters, walking quality, and balance. Walking parameters will be speed (m/s), step length (m), and cadence (steps/min). They will be measured during the participant walking at comfortable speed over 10 m of a 16-m walkway (i.e. 10-m Walk Test). Walking quality will be measured as maximum hip extension at the end of stance (deg) and maximum knee flexion at the beginning of swing (deg) using kinematics (Optotrak® system – Northern Digital, 100 Hz; Waterloo, ON, Canada). Balance will be measured using the Timed Single Limb Stance Test (17) for each lower limb (paretic and nonparetic). Participants will be asked to stand barefoot on one limb, with the other limb raised so that the raised foot will be near but not touching the ankle of their stance limb, and to focus on a spot on the wall at eye level with their arms crossed over the chest. Time will end when: (1) arms move (i.e. uncrossed); (2) elevated foot moves (i.e., toward or away from the standing limb or touches the floor); (3) weight-bearing foot moves (i.e., rotates foot on the ground); or (4) 45 s has elapsed. Data monitoring body An independent researcher will monitor any adverse events. Sample size Eighty-eight participants will be recruited with walking capacity as the primary outcome measure. The sample size has been calculated to reliably detect a between-group difference of around 20% in walking capacity (60 m), with 80% power at a two-tailed significance level of 0·05 and an expected dropout rate of 5%. In a randomized trial of a similar population of communitydwelling people after stroke (18), the distance walked in sixminutes by participants who could walk > 0·4 < 1·2 m/s was 294 (SD, 97) m using the same measurement procedure to the present © 2014 The Authors. International Journal of Stroke © 2014 World Stroke Organization
protocol. The least number of participants needed to detect a 60 m difference between two independent groups is 44 participants per group. Statistical analysis Data collection will yield eight variables that reflect some aspect of walking ability: • Walking capacity – distance (m) • Walking parameters – speed (m/s), step length (m), cadence (steps/min) • Walking quality – max hip ext at end stance (deg), max knee flex at beginning swing (deg), and • Balance – time balancing on one leg (s) both paretic and nonparetic There are two factors (group × time), with repeated measures on the time factor. Two-way analyses of variance with repeated measures at all time-points for all outcomes will be reported to evaluate statistically significant between-group differences. Group mean difference and 95% confidence interval will be reported to evaluate clinically significant between-group differences. Study organization This clinical trial is being conducted in accordance with approval received from the institutional ethical committee (Comitê de Ética em Pesquisa da UDESC 93/2010).
Discussion If backward treadmill walking can improve walking capacity more than forward treadmill training in stroke, it may have broader implications as walking capacity has been shown to predict physical activity level and community participation (19).
Summary and conclusions Because backward walking is a challenging activity, the results of this trial may produce important advances in walking rehabilitation and increased independent community walking in people after stroke.
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© 2014 The Authors. International Journal of Stroke © 2014 World Stroke Organization