There are several factors that must be considered when prescribing resistance exercise to persons with physical disabilities. Most importantly, the resistance training program will depend on the severity of the disability and its associated conditions. Some clients will be able to train at very high intensity levels, while others will only be able to perform at minimal levels of resistance (i.e., lifting a body part against gravity). The training load (number of sets and repetitions, frequency, rest interval between sets) will also vary in persons with similar and different types of physical disabilities. For example, two individuals with multiple sclerosis may require a completely different training regimen because of the type of multiple sclerosis, length of time they have had the condition, and their age. On the contrary, two individuals with stroke and cerebral palsy may have a similar program, because they exhibit the same associated conditions (i.e, non-progressive hemiplegia, spasticity) and are at the same baseline level of strength.
A major determinant of training volume is the amount of muscle mass that is still functional. Persons with paralysis, hemiplegia, impaired motor control, or limited joint mobility have less functional muscle mass and will therefore require a lower training volume. For individuals who cannot lift the minimal weight on certain resistance machines, resistance bands or cuff weights are recommended. If bands and cuff weights are too difficult, use the person's own body weight as the initial resistance. For example, lifting an arm or leg for 5 to 10 seconds may be the initial starting point for clients with very low levels of strength.
The training load will also depend on the type of disability. In general, individuals who do not have a progressive disorder (i.e., spinal cord injury, cerebral palsy) will be able to work at higher intensity levels than persons with progressive disorders (i.e., multiple sclerosis, post-polio).
Training volume will also depend on the person's health status. For example, a person who has had a stroke or has hypertension should not perform high intensity exercise. Individuals who are seizure-prone or fatigue easily require a reduction in training volume. Many individuals with physical disabilities who have been inactive for much of their lives need only a small amount of resistance exercise during the initial stage of the program to obtain a training effect. How quickly a person is able to progress during the conditioning stage will depend on the person's health status. For individuals who start out at very low levels of strength, significant improvements can be made with very light resistance.
Modes of resistance exercise consist of three general categories: free weights, portable equipment (i.e., elastic bands, tubing), and machines. Any of these modalities is acceptable for improving strength levels except in cases where the individual is at risk for injury. For example, persons with multiple sclerosis and cerebral palsy often have impaired motor control and may have a higher risk of dropping a free weight or having an elastic band snap back too quickly. When an instructor feels that the resistance mode presents a danger to the client, the exercise routine should be either adapted (i.e, securing the weight to the hand, changing the movement) or substituted with a safer piece of equipment.
Some experts argue that free-weight exercises have greater value for persons with physical disabilities because the resistance can be tailored to resemble a functional daily activity (Lockette, 1995). Free weights also require the action of stabilizing muscles around the torso and joints while lifting and lowering the resistance, which are muscle groups that need strengthening in persons with physical disabilities in order to maintain the ability to perform ADL and IADL. However, free weights require good trunk stability and may be difficult to perform in individuals who have severe limitations in motor control and coordination.
In clients with very low strength levels, gravity-resistance exercise may be all that the person is capable of doing. Performing 8-12 repetitions of a certain movement, such as abducting an arm or extending a leg, may be a good entry point. These exercises can be used with extremely weak musculature, while other modes of resistance exercise can be used with stronger muscle groups. Once an individual is able to complete 8-12 reps of a gravity-resistance exercise, the person could progress to free weight, bands or machines. If a client is unable to move a limb against gravity because of extreme weakness (often seen in the late stages of multiple sclerosis or in person with high-level quadriplegia), the instructor could place the limb in a certain position (i.e., abduction) and have the client hold the position isometrically for a few seconds or longer.
Active-Assistive exercise may be required for certain individuals who do not have enough strength to overcome the force of gravity. The instructor can assist the client in performing the movement by providing as much physical assistance as necessary to complete the repetition. At various points in the concentric phase (against gravity), the instructor may have to help the client maintain the resistance. During the eccentric phase (with gravity), the instructor controls the movement so that the weight is not lowered too quickly. In many instances, active-assistive exercise can be used with severely weak musculature, while active resistance exercise (performed without assistance) can be used with stronger muscle groups.
The instructor should make every effort to avoid fatigue and delayed-onset muscle soreness in individuals with physical disabilities. Although, this is a common side effect of any new resistance training program, it could present a problem for persons with physical disabilities if the soreness prevents them from conducting their normal activities of daily living (ADLs). Even though a client with a physical disability may aspire to make rapid gains in strength and can train at a moderate to high intensity level, the instructor should be cautious in not overworking the muscle groups, particularly in clients with progressive disorders. Use light resistance for at least the first month of the program (30 to 50% of 1-RM) and only proceed to higher training loads if muscle soreness and fatigue are not present.
If soreness in certain muscle groups prevents the person from performing routine daily activities, the exercise should be stopped until the pain subsides. If it continues after the program resumes, the instructor may need to reduce the training volume or avoid certain exercises that incur pain or fatigue. If there are prolonged bouts of pain or soreness 24 to 48 hours after exercise, the client should consult with his or her physician to determine the cause.
Developing the greatest amount of strength in the affected muscle groups may result in a 'reservoir' of strength that can be help decrease the severity of an exacerbation. Theoretically, the more muscle strength one has before an exacerbation, the more likely he or she will be able to maintain a high enough level of strength to stay above the 'physical dependence' threshold. Progressive disorders (i.e., multiple sclerosis) make it very difficult to determine the success of the resistance training program. However, the general feeling among rehabilitation professionals is that improvements in strength may help delay the progression of muscle weakness and permanent disability. If an individual achieves a gain of 30 to 40 percent in strength before an exacerbation, a loss of strength may still keep the individual at a high enough level to still be able to perform ADL and IADL.
Many physical disabilities result in hand dysfunction. This may make it difficult to grasp barbells or handles on different strength machines. There are several versions of specially-designed gloves that are available commercially that will allow the person's hand to maintain contact with the resistance equipment. Gloves will also protect the hand from injury while performing resistance training routines. Participants who do not have good grip strength can use wrist cuffs or leather mitts with velcro and buckles to secure their hands to dumbbells or weight equipment. Many individuals with physical disabilities will exhibit asymmetrical weakness or will have a disproportionately greater amount of weakness to the flexor or extensor muscle groups. This will depend on where the injury site is in the brain or spinal cord and whether or not the condition is progressive in nature. It is important to evaluate individual muscle groups on both sides of the body, as well as anteriorly and posteriorly, to isolate the degree of weakness to key muscle groups.
Individuals with asymmetrical weakness will often 'hike' their body toward the weaker side in order to compensate for this weakness while lifting the resistance. This could impose mild or moderate muscle strain. Make sure that the client is lifting the weight with proper form. If there is a tendency to 'hike' the body, lower the resistance and emphasize good form.
Blood pressure should be monitored frequently during the early stages of the program. In some individuals with physical disabilities (i.e., stroke, SCI), hypertension or hypotension is a common problem. It is recommended that blood pressure be measured before exercise, and before and after each set. Once the client adjusts to the program and there no wide fluctuations in blood pressure, it can be measured before and after each training session.