Stroke survivors often have low levels of physical fitness and muscle strength, which impact their ability to perform everyday activities and adversely affect their household and community independence. There is greater awareness now of the need for patients to practice everyday actions intensively in order to regain motor control. However, it is only recently that interest has turned to the physiologic effects of inactivity—especially the effect deconditioning has on an individual’s ability to engage in motor training at a level necessary to improve functional performance and promote brain reorganization (Carr & Sheperd, 2011).
Low aerobic capacity limits a person’s ability to practice ADLs and increases the risk of falls and dependence on others. It is also a significant determinant of poor bone health in individuals with chronic stroke. Reduced cardiorespiratory fitness and inactivity appears to be related to a combination of pathologic (comorbid cardiovascular disease), physiologic (decreased muscle activation and motor control), and environmental factors (little opportunity or incentive for physical activity). For elders, these factors may be combined with an age-related decline in cardiorespiratory fitness reported to be approximately 10% or greater per decade (Carr & Sheperd, 2011).
The development of a task-specific training model of rehabilitation with emphasis on activating motor learning processes provides a framework for functional rehabilitation. For example, simple methods of providing increased intensity in the early period include specific and repetitive practice of standing up and sitting down, aimed both at improving the effectiveness of performance of standing up itself but also the person’s ability to perform the action with sufficient repetitions to produce an efficient performance in terms of O2 uptake (Carr & Shepherd, 2011).
Exercise Therapy
Exercise therapy refers to a regimen or plan of physical activities designed and prescribed for specific therapeutic goals and intended to restore optimal functioning (Veerbeek et al., 2014). The major forms of exercise to improve physical activity for individuals after stroke include:
- Aerobic fitness training
- Functional task and balance training
- Strength and endurance training
Weakness of the extremities is a particularly common impairment after a stroke because of damage to upper motor neurons, which leads to weakness and atrophy of muscles. Weakness in the lower extremities affects strength and balance and causes difficulty with mobility and walking. Weakness in the upper extremities affects the use of the hand and arm and affects the ability to do ADLs. Weakness is usually not confined to the extremities but also affects the muscles of the trunk, neck, face, and eyes.
Weakness and paresis following stroke commonly contributes to decreased active and passive range of motion of the involved joints. Profound hemiparesis can lead to joint contractures, which severely impair mobility and may lead to pressure ulcers. Passive and active exercises are used to reduce the risk of secondary musculoskeletal impairment from decreased joint range of motion.
Stroke can worsen pre-existing conditions such as osteoarthritis, or can lead to osteoarthritis by producing muscle imbalances that result in inappropriate forces across joints. Maladaptive activity patterns or postures can develop in upper or lower extremities after stroke as an individual attempts to regain function. For example, hyperextension of the knee is a common maladaptive pattern that allows for weight-bearing on a weakened or paretic lower extremity, but it can cause osteoarthritis and joint pain if this pattern continues over time.
In 2014 the American Heart Association and the American Stroke Association issued a scientific statement containing an overview of the evidence on physical activity and exercise for those who have survived a stroke. Their summary shows the clear benefit of aerobic exercise and strength training. Physical activity should emphasize low- to moderate-intensity aerobic activity, muscle-strengthening activity, reduction of sedentary behavior, and risk management for secondary prevention of stroke (Billinger et al., 2014).
Post stroke exercise programs are increasingly structured around functional activities rather than repetition of individual exercises. For example, to improve walking, the task should be broken down into specific activities that build toward walking. When possible, technology can be used to provide support, reduce the risk of falling, and reduce the burden of weight-bearing when practicing a task. This is particularly helpful with gait, in which a person’s weight is partially supported using an overhead harness and a treadmill.
Functional Exercise
[This section is taken largely from Carr & Shepherd, 2011.]
It is increasingly acknowledged that the rehabilitation team must increase the time spent in meaningful exercises and task practice to meet the needs of brain reorganization, skill relearning, and improved physical and mental fitness. The low intensity, low duration, and low frequency of physical therapy common in many rehabilitation centers, following outdated and insufficiently challenging therapy models of intervention, sometimes for as little as 30 minutes to 1 hour per day, severely restrict the optimal level of recovery required for participation in daily and social activities after stroke.
Therapists need to move away from reliance on one-to-one therapy to a model in which the patient practices not only in individualized training sessions with a therapist but also in groups, and in circuit training. In this model, patients practice at work stations set up for weight-bearing strength training exercises, and are encouraged to practice specific actions. Patients can be semi-supervised and assisted as necessary by therapists and aides who have similar attitudes and methods to those who work in sports training.
The modern rehabilitation workspace needs to provide an environment built to encourage and challenge physical activity. Such an environment may include a suspended harness system that allows practice of balancing and walking tasks, feedback and computerized devices to provide information and incentive, exercise machines such as treadmills with harness suspension, stationary bicycles, including an electronically braked isokinetic ergometer, and stepping machines. Some centers are developing and testing electromechanical training aides, including robotic devices and virtual reality systems. Even simple technologic aids can increase time spent in physical and mental activity by enabling patients to practice independently. Assistive devices and the assistance of therapy aides can drive physical participation and increase intensity of practice, motivation, competition, and personal responsibility. Patients can also work together, one assisting the practice of the other.
A modern rehabilitation program can include, in addition to task-relevant exercises, a combination of aerobic, strengthening, and flexibility exercises. Active exercise improves exercise tolerance if well prescribed, but exercises need to be sufficiently intensive and in weight-bearing positions. Exercises that share similar biomechanical characteristics—for example, weight bearing exercises that involve flexion and extension of hips, knees, and ankles—are likely to improved stair walking, squatting, and standing up and sitting down. Exercises in water may also have positive training effects, and when properly supervised can increase fitness, which is particularly useful for people with painful arthritic joints who find it difficult to exercise.