The use of strengthening exercises in post-polio sequelae. Methods and results

Review article : The late effects of poliomyelitis: aetiology and rehabilitation

Decades after their acute infection, many polio survivors are suffering renewed muscle weakness, increasing respiratory difficulties, musculoskeletal pain, fatigue and cold intolerance which lead to a 'second disability'. Some symptoms are due to chronic mechanical strain caused by using joints rendered unstable after the acute infection. The cause of others, such as postpoliomyelitis muscular atrophy, is . unknown although overuse, ageing, disuse atrophy and metabolic fatigue of axon sprouts in the abnormally large motor units may play a role. The aim of rehabilitation is to halt the progress of the condition and reduce its physical and psychological impact. Reduction in strenuous activity is important. The use of orthoses or a wheelchair may help to reduce pain and the energy cost of mobility. Respiratory aids such as the cuirasse can improve health. Counselling and peer group support can help the patient to accept his physical limitations.

Response to resistive strengthening exercise training in humans with neuromuscular disease

The role of strengthening exercise to potentially improve weakness and the functional abilities of persons with neuromuscular diseases is controversial. There are questions about the ability of diseased skeletal muscle to respond to resistance exercise, particularly in light of concerns about weakness induced by exercise. Numerous studies show promising results of strength training, although methodologic issues limit conclusions. This article reviews current knowledge in this area and provides recommendations for future investigations.

A comparison of the effects of exercise and lifestyle modification on the resolution of overuse symptoms of the shoulder in polio survivors: a preliminary study

OBJECTIVE

To compare the effectiveness of exercise and lifestyle modification therapy in treating shoulder symptoms in polio survivors with lower-extremity weakness.

DESIGN

A randomized parallel group study.

SETTING

Research laboratory.

PARTICIPANTS

Twenty-three subjects recruited from a cohort of 194 polio survivors who had participated in a previous study had bilateral hip-extensor and knee-extensor weakness and reported experiencing shoulder pain on a regular basis with daily activity.

INTERVENTIONS

Subjects were randomly assigned to 1 of 3 treatment groups. Members of group 1 were placed on a home exercise program that focused on strengthening their hip and knee extensors. Members of group 2 were instructed in lifestyle modification techniques designed to avoid shoulder overuse. Members of group 3 received both interventions.

MAIN OUTCOME MEASURES

Shoulder symptoms were quantified in terms of number and severity. Isometric strength of bilateral hip and knee extensors was measured with a hand-held dynamometer.

RESULTS

Symptoms improved in all 3 groups. However, members of the exercise-only group (group 1) were the only ones to show a significant difference in both number and severity of symptoms when pre- and posttreatment values were compared.

CONCLUSIONS

Both exercise and lifestyle modification therapies that focus on reducing the stress related to lower-extremity weakness are effective in treating shoulder overuse symptoms in polio survivors. A trend toward greater improvement in shoulder symptoms in subjects who participated in the exercise program and who also showed a trend toward increased knee-extensor strength supports muscle strength and/or endurance as a key factor.

Endurance training effect on individuals with postpoliomyelitis

OBJECTIVE

To determine the effects of an endurance training program on the exercise capacity and muscle structure and function in individuals with postpolio syndrome.

DESIGN

Preexercise and postexercise testing was performed with muscle strength evaluations using isokinetic testing as well as hand-held Myometer. Muscle fatigue was determined by use of isokinetic testing, and endurance was determined by exercise testing. Enzymatic evaluation was performed with muscle biopsies taken at the same site; preexercise and postexercise muscle cross-sectional area was measured by computed tomography. Disability and psychosocial evaluation was performed by a Functional Status Questionnaire.

SETTING

A university.

SUBJECTS

Seventeen postpolio subjects ranging in age from 39 to 49 years volunteered for a 6-month combined endurance and strength training program. They had a history of acute poliomyelitis at least 25 years earlier and were able to walk with or without aid.

INTERVENTION

Twelve of the subjects (mean age 42 years) completed the program, attending an average of 29 sessions, which were offered for 60 minutes twice a week.

MAIN OUTCOME MEASURES

Strength, endurance, enzymatic activity, and cross-sectional area were measured 3 months before the beginning of training, just before training, and at the completion of the exercise program.

RESULTS

Knee extension was reduced to an average of 60% of control values and did not change with training. Strength measured with a hand-held Myometer increased significantly for elbow flexion, wrist extension, and hip abduction. Exercise test on a bicycle-ergometer showed significant reduction (6beats/min) in heart rate at 70W and increase (12beats/min) in maximal heart rate with training. The training program could be performed without major complications and resulted in an increase in muscle strength in some muscle groups and in work performance with respect to heart rate at submaximal work load.

Post-polio syndrome. An emerging threat to polio survivors

The manifestations of post-polio syndrome typically occur 20 to 40 years after an acute episode of poliomyelitis and are confined to previously affected muscles. Because of motor unit remodeling and direct mechanical damage, weakness increases in individual muscles until it exceeds their narrow margin of reserve and becomes clinically apparent. Although the exact cause is not clear, generalized weakness often occurs when several muscles are affected and various postural limb strategies used by the patient are no longer able to compensate for the loss of muscle strength. The mainstays of treatment are life-style changes to avoid overexertion and use of light-weight orthoses and assistive aids to unload the extremities. Exercise and surgery have a limited role in management.

The effects of long-term non-fatiguing resistance exercise in subjects with post-polio syndrome

Measures of torque were used to evaluate changes in muscle strength and endurance in 17 patients with post-polio syndrome who did prescribed resistance exercise for up to 2 years. Exercise compliance averaged 75%, with 16 subjects increasing the weight lifted in training. Maximum torque was significantly increased in the exercised muscle compared to the control muscle; no difference was seen in muscle endurance. Individuals with post-polio syndrome can increase muscle strength by doing non-fatiguing resistance exercise, but they should undergo quantitative testing of muscle strength a minimum of every 3 months to guard against overwork weakness.

Postpolio syndrome

The recurrence of symptoms many years after the rehabilitation of individuals who survived the acute illness, poliomyelitis, is a major concern. The purpose of this article is to provide information to the nurse practitioner (NP), who, as a primary health care provider, may be the first health professional to encounter persons with such complaints. Although no cure has been identified, diagnosis and treatment is available and is important to the psychosocial well-being of those who suffer from postpolio syndrome. This article reviews research on the syndrome including etiology, pathophysiology, symptoms and management, psychological issues, and the role of the aging process. Some areas where further research is indicated are also identified.