Importance of Specificity, Amount, and Intensity of Locomotor Training ...

Importance of Specificity, Amount, and Intensity of Locomotor Training to Improve Ambulatory Function in Patients Poststroke T. George Hornby, PT, PhD,1–4 Donald S. Straube, PT, PhD, NCS,1 Catherine R. Kinnaird, MS,3 Carey L. Holleran, MPT, NCS,3 Anthony J. Echauz, DPT,3 Kelly S. Rodriguez, MPT, NCS,3 Eric J. Wagner, BS,3 and Elizabeth A. Narducci, DPT3,5 1

Department of Physical Therapy, University of Illinois at Chicago, Chicago, Illinois; Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois; 3 Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, Illinois; 4 Department of Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, Illinois; 5 Department of Physical Therapy, Walsh University, North Canton, Ohio 2

The majority of individuals poststroke recover the ability to walk overground, although residual impairments contribute to reduced walking speed, spatiotemporal asymmetries, inefficient gait, and limited walking activity in the home and community. A substantial number of studies have investigated the effects of various interventions on locomotor function in individuals poststroke; these studies vary widely in types of tasks practiced, the amount of practiced activities, and the intensity or workload during the intervention. In contrast, basic and applied studies have identified specific parameters of training that could be applied towards treatment of patients poststroke. More directly, the specificity, amount, and intensity of walking practice are thought to be critical variables of rehabilitation interventions that can facilitate plasticity of neuromuscular and cardiopulmonary systems and result in improved locomotor function. In the present commentary, we delineate the evidence and physiological rationale for providing large amounts of high-intensity locomotor training to improve ambulatory function in individuals poststroke. Additional evidence is presented to indicate that improvements in non-walking tasks, such as static balance and performance of transfers, may also occur following locomotor training. We further evaluate previous and more recent studies in the context of these parameters and provide suggestions for providing locomotor training for patients with stroke in the clinical setting. Key words: locomotion, gait training, intensity

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early 800,000 people in the United States experience a stroke each year, 1 with 60% to 75% surviving 1-year following stroke, resulting in a prevalence of over 6 million individuals. 2,3 Approximately 80% of stroke survivors experience acute hemiparesis,4–6 with more than 70% experiencing persistent motor deficits.4,5 Although a substantial proportion of these patients (80%–90%) achieve independent ambulation, a large proportion (up to 80%) experience considerable gait deficits,7,8 including reduced gait speed and timed walking distance, asymmetrical walking patterns, postural instability, and decreased efficiency. The ability to safely ambulate is a primary factor that determines whether a patient is discharged to a nursing facility or home and whether a patient returns to premorbid levels of social and occupational activities.9 For those who are discharged to home, the total amount of walking activity performed in the home and community remains extremely

limited,10 further reducing the probability of their successful return to previous levels of participation.11,12 A sizable body of evidence has indicated that substantial recovery in lower limb motor function occurs in the first 3 months poststroke,13–16 followed by significantly smaller improvements thereafter. Previous studies have demonstrated that intensive physical rehabilitation paradigms that focus on participation in specific tasks (ie, task specificity) given within the early poststroke period may improve locomotor recovery to a greater extent than do traditional therapeutic techniques.17–19 In particular, lower limb recovery, typically reflected in walking ability, can be augmented substantially in patients with varying levels of disability when Top Stroke Rehabil 2011;18(4):293–307 © 2011 Thomas Land Publishers, Inc. www.thomasland.com doi: 10.1310/tsr1804-293

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they are provided with task-specific interventions early poststroke.20,21 Even in the chronic stages following stroke, experimental trials indicate that substantial changes in walking ability can occur when patients are provided with specific physical therapy interventions. There are, of course, many interventions tested in the research laboratory and utilized in the clinical setting that have demonstrated variable efficacy for improving walking, and questions remain regarding which interventions are most effective for improving walking ability in individuals poststroke. In this present article, we review research findings of key variables that are relevant to locomotor training poststroke. We address the parameters of specificity, amount, and intensity of locomotor training, all of which are thought to be critical factors that facilitate recovery following neurological injury. We highlight the favorable effects on performance of walking and non-walking tasks following large amounts of high-intensity, task-specific locomotor training, and we describe the potential barriers to the delivery of high-intensity, task-specific locomotor training in the clinical setting. Finally, we provide recommendations for organizing rehabilitation sessions, which may facilitate delivery of such training during clinical treatment sessions.

provide walking practice aimed at improving independent ambulation, provided on a treadmill or overground. This definition may therefore include various training protocols such as circuit training, where substantial walking practice is provided within and between exercise stations. The rationale behind supported treadmill training is to provide stepping practice to individuals in a safe environment, even to those who may not be able to step or stand independently. Early studies investigating the efficacy of LT performed on a treadmill with partial BWS demonstrated substantial improvements in recovery of independent walking ability and other motor functions in non-ambulatory stroke survivors.23,24 Additional studies suggested that the use of partial BWS may be beneficial in improving walking-related outcomes in individuals who had greater initial gait impairments (ie, gait speed