INTRODUCTION

States et al1 should be commended for their succinct and comprehensive contribution to the stroke rehabilitation literature. In their recent systematic review,1 the authors sought to determine the influence of overground gait training on locomotor function in individuals with chronic stroke. Although they concluded that insufficient evidence exists to suggest that overground gait training can be used to improve gait function, their work acts as an excellent reminder of several key points. First, it is noteworthy that they chose to focus their analyses on individuals with chronic hemiparesis poststroke (more than 6 months' duration). The results of the meta-analysis revealed gains in performance variables (eg, gait speed, Timed Up and Go, six-minute walk) immediately after training, providing further evidence that mobility gains can be achieved even in the chronic stages after stroke. Second, the chosen intervention was "overground gait training." Improving locomotor function is a major goal of rehabilitation, and if patients want to improve walking, they need to practice walking. Overground gait training represents the most task-specific approach in improving gait for individuals with hemiparesis after stroke. With so much attention focused recently on the use of body weight-supported treadmill training (BWSTT) or robotic-assisted gait training, it is important to remember that during normal day-to-day activities, our patients walk overground, not on a treadmill or with robotic assistance. Thus, it is refreshing to be reminded of the importance of overground gait training for practicing functional mobility.

TRAINING INTENSITY

Despite the perceived importance of overground gait training, it was disheartening to find that only nine studies that used overground gait training were identified for incorporation into the meta-analysis. Clearly, we need further research to more effectively evaluate the influence of overground gait training and/or its component parts. As defined by States et al, overground gait training does not seem to have the level of evidence that we may perceived it to have. This may be discouraging for physical therapists who practice overground gait training on a regular basis and may require us to rethink the interventions that we provide. However, it is important to note that the nine studies identified by States et al varied considerably in the type, quantity (dose and frequency), and intensity of training. Although many of the cited articles did not adequately define their rehabilitation protocols, their limited descriptions suggest that they used extremely broad and varied approaches, sometimes involving little, if any, actual "walking."2-6 Indeed, many of the early studies investigating the use of BWSTT in individuals post-stroke found significant improvements over conventional physical therapy, possibly because of the use of pregait activities and limited actual stepping practice provided during the conventional therapy sessions.7,8 Conversely, repeated practice of actual walking provided overground can provide many of the specific sensory cues thought to promote recovery of independent walking.9 Specific afferent inputs provided repetitively during locomotor training, including maximizing lower limb weight-bearing during stance,10 training at gait velocities approximating normal walking speeds,11 and generating reciprocal lower limb kinematics associated with locomotion,12 are thought to facilitate locomotor recovery in individuals with stroke. Such repetitive stepping practice is thought to enhance the output from spinal centers and residual descending pathways for improved locomotion. Randomized trials performed in subacute stroke13 and subacute spinal cord injury,14 which compared therapist-assisted BWSTT vs overground gait training, revealed very small or no differences between group outcomes, suggesting that massed practice of stepping was potentially the key ingredient for recovery, whether performed on a treadmill or not. The growing evidence15-17 of intensive massed practice as a part of chronic stroke rehabilitation suggests that we must ensure sufficient stepping practice to produce the greatest gains in locomotor function. Despite this assertion, several of the articles cited by States et al incorporated alternative approaches.

MEASURING FUNCTIONAL CHANGE

In discussing their findings, States et al raised excellent questions related to appropriate measures for documenting improvements in gait. Although no benefit to the use of overground gait training was observed with the Rivermead Mobility Index or Stroke Rehabilitation Assessment of Movement, significant but small improvements were seen in gait speed, endurance, and the Timed Up and Go at the conclusion of training. The former outcome measures represent gross motor functions, incorporating tasks (some even focused on upper extremity movements) that are nonspecific to gait. The authors note the importance of using newly developed multidimensional performance variables to more accurately document change in response to training.

Finally, the authors present an intriguing hypothesis that overground gait training may be better suited in educating patients regarding safety, while encouraging participation in therapeutic exercise to improve strength, cardiovascular fitness, movement efficiency, and agility. Rather than simply providing a context to practice stepping, an additional benefit may thus be the alleviation of a fear of falling while walking. In this case, individuals are better prepared to participate in activities that are important to them and can further enhance activities such as transfers and stair climbing. Their hypothesis fits with the belief that overground gait training represents one component of a comprehensive locomotor training program. Determining how to optimize current overground gait training and how it meshes with other forms of locomotor training will be important future work.

REFERENCES