Neurorehabilitation was revolutionized by the discovery that the mature nervous system, far from being static, is constantly molded by experience. Hebb's1 insights in the 1940s regarding associative learning and the discovery in the 1970s of long-term potentiation were just the beginnings. The idea that neural plasticity is activity-dependent (ie, occurs only in the circuits that are active) really began to flourish following the publication in 1984 of a review article in Science by Black and colleagues.2 The article summarized the evidence that the membrane depolarization and ion flux associated with the activation of neurons in a circuit can change the type of neurotransmitter that is released. Shortly thereafter, the term "activity-dependent plasticity" first appeared in an article title associated with a study showing that the structural morphology of synaptic connections is modified in response to the stimuli to which the neurons are exposed.3 That synaptic modulation and structural transformation accompany neural activation of specific, related circuits are now accepted as the underpinnings of neuroplasticity.

Applying the concepts of activity-dependent plasticity to motor learning, in the late 1980s Carr and Shepherd4 advanced a model of practice that emphasized task- and context-specific training of real-world function and biomechanically normal movement. With positive functional outcomes, this approach became one of the dominant (if not the dominant) approaches for neurorehabilitation in the United States. However, an odd phenomenon occurred in the world of spinal cord injury rehabilitation in 2002 following the popular media clamor over a case report describing a high-profile subject with chronic complete tetraplegia.5 The publication described recovery of some voluntary wrist movement and ability to take steps when in a pool. The report suggested that an activity-based recovery program, the main component of which (according to the authors) was lower extremity cycle ergometry, was chiefly responsible for the observed recovery. Since that time, many of those in the world of spinal cord injury rehabilitation have adopted the term activity-based therapy. It seems somewhat curious that while the approaches used in spinal cord injury rehabilitation are similar in concept and application to those used in other neurological populations, the term activity-based therapy is used only in the world of spinal cord injury. Does this terminology capture the crucial elements of our interventions? Is it consistent with the evidence from the motor learning literature? Are we doing our patients and our profession a disservice by using such broad terms to describe what we do?

At a recent presentation I asked the very questions posed above, and an observant colleague noted that the word "activity" in activity-based therapy is in step with language of the International Classification of Functioning, Disability, and Health (ICF). No doubt the word serves as a reminder that "execution of a task or action by an individual"6 is the critical element. Based on what we know of motor learning then, if activity-based therapies are to optimize functional restoration then they must focus on functional tasks. Task-oriented (-specific) training, repetitive task practice, and functional task practice are the critical elements of motor learning. For this reason, the term activity-based therapy can be misleading to the consumer, implying that it is activity, rather than task-related training that is the critical element. There is no evidence of which I am aware that random, undirected activity influences the ability to perform skilled motor behaviors. Conversely, despite a search of the literature, I could identify no studies of motor learning that referred to their approach as activity-based therapy.

The terms we use to describe our practice have implications for how those outside our profession view our practice. When working with a patient to restore ability to perform functional movement the physical therapist is informed by a wealth of knowledge-expertise in pathokinesiology; the ability to objectively evaluate impairment, functional limitations, and participation restrictions; understanding of how to structure the task to be challenging but with potential for success; development of a training schedule incorporating blocked or random practice; emphasis on intrinsic feedback and well-timed explicit feedback; and concrete goals that take into account the patient's own goals and lifestyle. To lump the end result of this knowledge and expertise into the ball-of-wax term, activity-based therapy does a disservice to decades of physical therapists-expert clinicians who have spent years developing their skills, researchers who have contributed to the motor learning literature, and leaders who have toiled for recognition of the unique contributions of our profession. The sum and substance were well-put by Alice in Wonderland's Cheshire Cat to paraphrase, it's important to mean what we say, and say what we mean.

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