Physical Activity for
Children with Physical Disabilities

Rebecca A. Battista ©2001

Abstract

Physical activity is critical to children with physical disabilities.  However, why are physically disabled children more sedentary when compared to able-bodied children?  Physiologically, the same variables and rules apply.  Aerobic ability, muscle strength and endurance, and increased range of motion will be discussed as to how they are trainable in a physically disabled child.  Programs for involvement in physical activity can be set up in similar ways for both disabled and able-bodied children, with only a few additional considerations.  All in all, exercise should be valued from a physiological perspective in a physically disabled child.  The findings from this paper are expected to encourage more participation of physically disabled children in physical activity.

Introduction

What are the physiological and health benefits of physical activity in children with physical disabilities?  Are children with physical disabilities trainable?  Physical activity is vital for maintaining a healthy lifestyle; however, not everyone responds to training in the same manner.  What are ways this can be accomplished?  Can physically disabled children be trained so far as to become elite athletes?

The physical disabilities in children include those which impair physical functions.  Examples are neuromuscular disease, including spina bifida, cerebral palsy, and muscular dystrophy to name a few.  The health status of children with physical disabilities is not remarkable.  They may be at risk for hypertension, cardiovascular disease, diabetes, osteoporosis, and obesity (Nelson & Harris, 1995).  How can these risk factors be eliminated?

Children are similar to adults as far as the possible risk factors associated with a sedentary lifestyle.  Exercise is one way to eliminate these risk factors.  For example, the United States Surgeon General's Report (1996) stated that regular physical activity might be the single most important health practice for promoting wellness.  Physical activity can decrease the risk of cardiovascular disease, some cancers, and osteoporosis, and can even improve mental health.  These factors can be applied to children with physical disabilities.

Physical activity variables to be discussed in this paper are maximal aerobic ability, muscular strength, muscular endurance, and body composition, to name a few.  These variables are trainable in adults to some extent, and are also trainable in both adolescents and children.  But what may be some factors that need be taken into consideration that may limit certain physiological parameters in disabled individuals?  Can these factors be overcome to some degree in a growing, physically disabled child?  An improved health status via participating in physical activity may be what is needed to decrease risk factors associated with children who have various physical disabilities (Nelson & Harris, 1995).

If adults are trainable, are children and adolescents?  Children and adolescents represent a group with a large degree of variability within; simply consider how normal growth, maturation and development affects children and adolescents.  Now add physical disabilities in children and adolescents to the mix.  Not only is there variability according to growth, maturation and development but now there is an additional variability according to disability.  Nonetheless, the question remains, even considering the differences, are disabled children and adolescents trainable?  Trainability is simply a response to a stress.  In what ways are physically disabled children trainable?  Can they experience the positive outcomes from participation in physical activity and sports?  Can they become elite athletes?   

Exercise can be positive.  It can relieve some symptoms related to the disability as well as provide the child with a better self-concept and a healthier lifestyle.  Research has indicated that a lot of disabled children are not physically fit. Is this because they are not able to become fit or because they are not participating in a fitness activity?  The following will provide information concerning what kinds of exercise or activity children with disabilities can perform and how it can be beneficial.

Review of Literature: Physical Activity
and Children with Physical Disabilities

           Physical fitness and sport participation are important for children.  Positive benefits can be seen in the following areas:  (a) physical and psychological health; (b) self-concept; (c) body awareness; (d) motor development; (e) sportsmanship; (f) competition; and  (g) social interaction (Lai, Stanish & Stanish, 2000).  Physical benefits include factors that will improve cardiovascular functions, muscular strength and endurance as well as assisting in normal range of motion.  The question is, how can these benefits be accomplished through physical activity?

           What is physical activity?  There are two ways to describe physical fitness, health related or performance related physical fitness.  The program or goals for physical fitness should depend on the goals of the individual (ACSM, 1995).  Health related physical fitness is fitness to improve overall health.  This would consist of alterations in cardiovascular ability, as well as increases in a specific ability such as number of sit-ups, skin-fold measurements used to determine body composition, and low back flexibility.  On the other hand, performance related physical fitness is fitness based on performances.  Examples would be time in the shuttle run, length jumped in vertical jump, and time held in the flexed arm hang.  These will provide a measure of variables such as strength, power, speed, endurance, and agility (Malina & Bouchard, 1991).

Why participate in physical activity?  Leading a sedentary lifestyle as a child with a physical disability may increase the risk of further health problems.  The risk factors associated with a sedentary lifestyle may compromise their desire to maintain their independence (Lai, Stanish & Stanish, 2000).  Along with wanting to maintain independence comes the risk for secondary factors such as obesity, further contractures, and diabetes, to name a few.  Physically disabled children should participate in such activities in order to prevent or lessen their chances of the above listed secondary risk factors, all of which are preventable through exercise (Nelson & Harris, 1995).  By performing aerobic exercise, which is exercise that stresses the cardiovascular system, risk of cardiovascular disease may decrease.  In addition, an increase muscle strength and endurance, and an increase flexibility may aid in preventing or worsening contractures  (Cooper, et al, 1999).

With the focus being children and adolescents, it becomes essential to consider the impact of physical activity on normal development of skills.  Physically disabled children should participate in activities that a typical child would enjoy.  These skills involve and utilize physical coordination, gross and fine motor skills, as well as proper communication which are crucial to the development of more advanced skills, skills needed in sports, for instance (Cooper, et al, 1999).  Development of skills are vital to a child, therefore as they grow and mature so should these skills (Longmuir & Bar-Or, 1994).  However, the problem for disabled children and adolescents becomes the opportunity for these play experiences.  Opportunities may be limited due to lack of having the skill, but also limited due to overprotective adults, societal factors, lack of time, and most importantly lack of a sufficient program (Longmuir & Bar-Or, 1994).

           Even though the disabled child will react to physical activity in similar manners as an able-bodied child, many disabled children continue to lead a more sedentary lifestyle.  Longmuir & Bar-Or (1994) surveyed 987 disabled children and adolescents that ranged in age from 6-20 years old.  Disabilities represented in this sample included, visual and hearing impaired, physically disabled and those with chronic illnesses.  Both girls and boys completed the survey.  The purpose was to investigate the physical activity habits of this population.  Results revealed very sedentary lifestyles for disabled children, especially during their second decade of life.  Percentages of activity amounts were reported as 39% were active, 32% were moderately active, and 29% were sedentary.  This compares to 10% of able-bodied youngsters who were sedentary (Longmuir & Bar-Or, 1994).  Why is it that more disabled children are sedentary versus able bodied?  This is a question that needs addressed.  In addition, this study reported that regardless of age or gender, which quite often play a role in physical activity in this age group, 52% felt “limited” in their ability to be physically active and 41% felt “limited” in their ability to participate in peer activities.  The authors acknowledged their lack of explanation for knowing what was “limiting” these youngsters from participation, however, they felt these youngster wanted to participate in spite of the perceptions they have developed (Longmuir & Bar-Or, 1994).  What can be done to change this “limiting” feeling?

One way to understand, to some degree, this “limiting” feeling is explained in the same study.  When activity level was observed, it was significantly negatively influenced by age (Longmuir & Bar-Or, 1994).  This is not surprising as the same phenomena occur in able-bodied children.  Activity levels were reported to have increased from age 6-10 years old, remained constant during adolescence age 10-15 years old and decreased from age 15 years old and older.  According the graph of age and activity level, the authors state there is a much faster decline in girls after age 15 years old (Longmuir & Bar-Or, 1994).  Conclusions were that physical activity decreased during adolescence after a peak that was reached by about age 10-12 years old.  From this it was also noted that children with a disability adopted a sedentary lifestyle in the second decade of life.   In addition, not uncommon to able-bodied children gender differences were most dramatic from age 10-14 years of age when girls had lower scores and even lower scores after age 16 years old (Longmuir & Bar-Or, 1994).  In other words, the physical activity habits of a physically disabled child are not unlike an able-bodied child, only a much larger percent are declining participation in physical activity.

           Why is it the more disabled children are sedentary versus able-bodied children?  Can physical activity change these habits?  Can physical activity improve their quality of life?  Most of these physically disabled children may be detrained or hypoactive (Bar-Or, 1986).  Disabilities can commonly cause “a cycle of deconditioning” in which the physical functioning decreases leading to a further reduction in physical activity levels (Cooper, et al, 1999).  Another reason may be related to their disability, a more pathophysiological problem resulting from their disability (Bar-Or, 1986).

            Positive benefits of physical activity.  But physical activity may positively benefit physically disabled children.  They may improve from activities consisting of something as simple as activity of a moderate intensity (Cooper, et al, 1999).  Physical activity may protect them from cardiovascular disease and high blood pressure (Cooper, et al, 1999).  It can also affect their body composition as well as the dietary needs, which all depend on normal requirements of a physical activity program (Cooper, et al, 1999). 

How to Improve Physical Fitness

There are four basic categories or ways to improve physical fitness.  Those four categories include, cardiovascular function, respiratory function, muscular strength and endurance, and functional range of motion.  The first category, cardiovascular function includes factors, which relate to the health of the heart.  Those factors include heart rate (HR), stroke volume (SV) and cardiac output (Q), all of which will be discussed later.  Nevertheless, an example of how these factors change can be explained with heart rate.  By participating in physical activity heart rate may decrease for both rest and exercise, meaning, more blood pumped per beat.  This is a positive adaptation. 

The second category, respiratory function includes the health of the lungs.  Although possible improvements in actual lung volumes are not possible as most are a function of the individuals body size, a decreased pressure on the lungs from losing weight is possible which can help in breathing rates (Brooks, Fahey, Baldwin & White, 1999).  Breathing requires the use of respiratory muscles, and these muscle react to exercise in much the same way are normal muscles.   If they are trained or stressed they will respond with increases and can eventually aid in breathing. 

The third category, muscular strength and endurance relates to increases in strength as well as with changes in body composition.  The changes in body composition that correspond with increases in muscle strength and endurance can alter the lean body mass.  Lean body mass consists of muscle mass, and can increase with increases in strength.  This in turn, can alter the percent body fat as lean body mass plus fat mass sum to give percent body fat (McArdle, Katch & Katch, 1991).  This is important because a change in body composition will decrease a physically disabled child's risk of becoming obese.  Under-activity versus diet or caloric intake may contribute to obesity.  Changes in body composition are related to a decrease risk of obesity (Nelson & Harris, 1995).

The last category includes the functional range of motion.  If range of motion is improved the benefits can be seen in increased flexibility and a possible decreased number of contractures.  Combined, all of these categories act to increase or better, the quality of life.

Physiological variables.  Physiologically, it is important to look at the variables responsible for increasing aerobic ability or VO₂max.  Aerobic ability or VO₂max is defined as the individuals capacity to use oxygen as an energy source (McArdle, Katch & Katch, 1991).  An equation that can very easily explain ways to improve aerobic ability is called the Fick equation (Brooks, Fahey, White & Baldwin, 1999).  The Fick equation states:  VO₂ = Q x (a-vO₂), where VO₂ is aerobic power, Q equals cardiac output, and a-vO₂ equals the difference in oxygen content between arterial blood and venous blood, in other words how much oxygen is being supplied.  In the Fick equation, the most important or trainable variable is the cardiac output or Q, as it is extremely difficult to change how much oxygen can be exchanged between the arteries and veins.  With cardiac output, it is important to realize what constitutes it, and that is heart rate (HR) and stroke volume (SV).  In fact, HR times SV equals Q.  In this equation, SV is the most trainable variable.   Stroke volume is the amount of blood that is pumped per beat, therefore if the heart can use more blood, aerobic ability can be improved.  In fact, SV does increase with exercise training (Brooks, Fahey, White & Baldwin, 1999). 

Energy cost of the activity plays an additional role in developing aerobic ability. Energy cost of an activity means an activity that expends more energy than what may be necessary (Bar-Or, 1986).  For example, for normal running and or walking the O₂ uptake is much higher in some disabled individuals; the O₂ uptake is above normal.  To correct this problem gait mechanics are observed.  For instance, a child with cerebral palsy may be provided with an orthosis to correct an inefficient gait pattern to allow that child more energy.  An orthosis is an external corrective device.  Energy cost of movement in children with neuromuscular disease is more because of the added stress of cardiovascular exercise as it leads to early fatigue; therefore, it may help to know the factors that increase O₂ cost in children with neuromuscular disease so one can reduce the cost (Cooper, et al, 1999).  For example, one study looked at the effects of a hinged ankle foot orthosis (AFO) on walking patterns in children with spastic diplegia (Level 1 and 2).  Subjects consisted of eight boys and two girls with a mean age of nine years old.  Anthropometric characteristics included a mean weight equal to 30kg and a sum of four skinfolds which equal to 33.9mm.  All subjects were able to walk independently regardless of the brace (AFO).  Laboratory testing consisted of collecting resting values as well as exercise values for ventilation (V_E), volume of O₂ (VO₂), volume of CO₂ (VCO₂), respiratory exchange ratio (RER), and heart rate (HR) and a treadmill test with and without the AFO at three varying speeds.  The variables were measured in the final 60 seconds of the third stage.  Results of the study found  the AFO reduced the O₂ cost of walking (Maltais, Bar-Or, Galea, & Pierrynowski, 2001).  Again, this may be a “quick fix” to improve the aerobic ability of a child, and provide them with more opportunities to participate in play, physical activity and sports. 

 Effects on physiological variables.  Any part of the above described variables (VO₂, Q, SV, HR, O₂ cost) will have an affect on the VO₂.  For instance, if venous return decreases then SV decreases, which will ultimately, decrease Q to then decrease VO₂ (Bar-Or, 1986).  Venous return is the amount of blood that makes it back to the heart.  If an individual is paralyzed or has some sort of loss of limb that causes blood to pool somewhere, VR may be affected and in turn will affect VO₂.  Maximal HR can be decreased (Bar-Or, 1986).  Many factors can inhibit normal heart rates for maximal exercise.  One in particular would be a decreased effect from the nervous system due to some sort of paralysis.  This will decrease HR and in turn can decrease VO₂max.  Maximal HR is determined by 220-age; however, this may not be accurate in all individuals especially in disabled individuals.  Another factor would be an insufficient O₂ supply in the blood due to some sort of respiratory and or circulatory or hematological defect (Bar-Or, 1986). Examples of these would be bronchial asthma where there are spasms of the smooth muscles of the bronchioles (Van De Graaff, 2002) or anemia where there is limited oxygen carrying capacity (Brooks, Fahey, White & Baldwin, 1999).  Both of these will ultimately effect the availability of oxygen to be exchanged and utilized. 

Characteristics of Basic Exercise Programs

Before a program can be started for physical activity, as with anyone prior to participation in a program, an evaluation should be completed.  A physically disabled child must be evaluated to the effect of their disability.  For instance, their normal physical and psychosocial growth and development should be evaluated (Lanphear, Liptak, & Wietzman, 1995).  In addition, the goals of the sport and exercise program need to individualized to them, similar as it is for anyone, and these should include the following: (a) health increase via cardiovascular conditioning; (b) decreases in obesity; (c) increases in muscular strength; and (d) increases in flexibility (Cooper, et al, 1999).  In other words, for what reason are they becoming active, for health or for performance?    For instance, when looking at spinal cord injured adults, Wells and Hooker (1990) stated that significant increases can be made in VO₂ max, anaerobic power, and lean body mass.  However, it is important to note the individual differences and the effects of the disability on limiting the ability to perform such skills (Wells & Hooker, 1990).  This may be true in all disability cases, and should encourage disabilities to be studied on an individual basis instead of being grouped together.

Features of an exercise program.  Certain features should be incorporated into each physical activity program.  Those factors include frequency, intensity, duration and mode.  Frequency means how often the activity is to be performed.  Intensity means how hard the activity is to be performed.  Duration means how long the activity should be performed.  To follow the recommendations from the American College of Sports Medicine (ACSM) for exercise prescription for an adult, who wants to improve V0₂max, the following should be included; participating in an activity approximately 3-5 days a week, at an intensity of 50-85% of VO₂reserve, for a time of 20-60 minutes using a mode of exercise that uses large muscle groups continuously (ACSM, 1995).  The most important variable to improve VO₂ max is intensity of the activity.  VO₂reserve is the amount of oxygen needed above resting oxygen.  However, without the use of a physiological lab to measure VO₂max to determine a percent of VO₂ reserve, how can one determine intensity?

            Measures of intensity.  There are two ways to determine intensity without the use of laboratory, HR and rating of perceived exertion (RPE).  HR can be used as a percentage of the predicted maximal HR.  As stated before, maximal HR is equal to 220 – age.  This method, as stated before, is not as accurate as if it was measured during a laboratory based VO₂max test.  However, it can help because a percent of HR reserve is directly related to VO₂max reserve (ACSM, 1995).  HR reserve is the HR above the resting HR.  It is important to understand HR is a very simplified way to measure intensity, it only requires little training, two fingers to take a pulse and a stop watch to measure the time.  The second way to measure intensity is through a RPE scale.  The RPE scale provides a subjective rating of intensity (Borg, 1982).  Considering the population is children, determining intensity may be one of the more difficult aspects to teach, observe and measure.

Effects on Physiological Variables

Physical growth.  If the population to be studied consists of children, shouldn’t normal growth be taken into consideration?  While much research has been done on able-bodied children as far as growth and increases in physiological factors related to physical activity, little has been done on children with physical disabilities.  Rintala, Lyytinen and Dunn (1990) did a study that used children with physical disabilities and a physical activity intervention used boys and girls age 7-11 years old that all were diagnosed with cerebral palsy.  These subjects underwent a four month training program in order to evaluate certain physical fitness components, balance and ball handling skills.  The physical fitness training consisted of a circuit type training that emphasized flexibility, muscle strength and endurance.  These sessions were twice a week lasting about 30 minutes each session for four months.  Sit and reach, a measure of flexibility, increased for the group to 14%.  Fifty meter dash times were lowered in only half the subjects with no percent change in the groups overall performance.  The nine minute run test improved for all subjects, but improved only 10% for three subjects (Rintala, Lyytinen, & Dunn, 1990).  Although improvements were seen in physical activity variables, the increase could be a function of normal growth and maturation considering the age of this group.  Physical fitness improved over the 30 minute training sessions for all the girls but not for all the boys possibly from the high level of physical fitness prior to the sessions (Rintala, Lyytinen, & Dunn, 1990). However, how was physical fitness assessed, through a total of all physical fitness related tests?  This was not very clear from the study.  There should be some mention of growth status of the subjects used in this study.  Typically, girls are better at flexibility at all times versus boys (Malina & Bouchard, 1991) and anaerobic performance does not improve until after puberty and increases in the aerobic fitness may be from simply adding any type of aerobic activity to the child's life (Rowland, 1996).  This brings up the matter of the effects of growth on physiological variables. 

Research that has been done on growing children recognizes limitations or confounding variables that influence aerobic ability.  One of those variables is growth.  As a child grows, their body grows; they get taller and heavier. These factor into aerobic ability as part of VO₂max concerns body weight.  The question becomes, is the increase in _VO2max due to a change in body mass, or the actual training the child has performed (Rowland, 1996).  This remains an unanswered question. 

Benefits from Physical Activity Considering
the Different Physiological Variables

How can exercise help a disabled child?  One study looked at the roles of exercise in assisting the assessment and clinical management of children with neuromuscular disease (Bar-Or, 1996).  It is beneficial to learn about the child’s fitness level as well as how to optimize the child’s condition and rehabilitation program (Bar-Or, 1996).  However, when testing disabled, it becomes important to realize the possible limitations from the disease therefore protocols may need to be modified in order to understand and make us of the values given (Bar-Or, 1996).  For example, with children who have some sort of neuromuscular disease, the following become important: determination of the rate of strength deterioration, high intensity short term power is sensitive to changes in function, and the energy cost of movement is important as far as the energy metabolism of the individual (Bar-Or, 1996).  As high energy cost of movement often leads to early fatigue. 

However, these aspects of physiology are also very trainable.  But it is important to understand the progress of the child’s disease and how that has or may affect the child’s physical fitness ability (Bar-Or, 1996).  Children with neuromuscular disease can certainly benefit from muscle strength retraining, it may be slower than able bodied but it does significantly increase (Bar-Or, 1996).  The a-vO2 transport system is also trainable as it simply may be a factor of efficiency and economy (Bar-Or, 1996).  What becomes the primary goal of any kind of physical fitness for disabled is to help maintain the individuals independence (Bar-Or, 1996).   

Program Considerations

When deciding on a program for a physically disabled child, certain conditions should be ascertained.  The physical activity program should be individualized according to the child and the disability.  Recommendations may be similar to an adult however, the following statement made by the ACSM guidelines should be followed, and that states “no matter how big, strong, or mature a young man or woman appears, remember that he/she is physiologically immature.”  In other words, children are not miniature adults and should be treated accordingly.  Nonetheless, a child with a physical disability should have the following questions addressed in an activity program.  According to disability these should be followed: (a) what are the cognitive abilities and social skills; (b) what effect does the disability or treatment have on stamina or skills; (c) will the specific sports activities pose a substantial risk to the health and well-being; (d) will specific interventions or modifications and conditions or preparation be required; (e) how could an activity be modified to allow a child to obtain a maximal benefit; and (f) what level of activity would be best for this particular child (Cooper, et al, 1999).

Elite Athletes with a Disability

Physically disabled adults can enjoy the benefits of physical activity.  Florence and Hagberg (1984) saw increases in VO₂max on patients with neuromuscular disease.  The subjects in this study all had non-progressive or slow progressive neuromuscular disease.  They participated in a twelve week endurance training program along with able bodied adults.  Results showed significant increases in VO₂max after only six weeks of training.  The authors concluded that the training program was able to not only increase VO₂max but allowed adaptations that would provide them with a more active, and normal lifestyle (Florence & Hagberg, 1984).  In other words, they can adapt to a training program.  Can the same hold true for children with neuromuscular disease?

Disabled children can be just as successful as able-bodied children.  In fact, they can even exceed expectations and become competitive athletes.  One study reported the physiological profile of an elite level swimmer.  The subject was a 14 year old achondroplastic dwarf.  The subject was tested on VO₂max, and body composition.  The VO₂max reported was 50.49 mL/kg/min.  Typically elite level swimmers of adult age report VO₂max values from 65-75 mL/kg/min.  As discussed previously, efficiency or O₂ cost plays a role in VO₂max.  This is true in this subject (Dummer, Battista, Tuffey, Riewald, & Sokolovas, 2000).  In fact, the test was performed while swimming and VO₂ max tests performed while swimming are dependent a lot more on skill versus aerobic ability (Brooks, Fahey, White & Baldwin, 2000).  Considering this factor it seems that efficiency of movement plays a large role.  Imagine what could be accomplished with an alteration in mechanics.  This provides an excellent example of a physically disabled individual that has the ability to perform at elite levels.  In other words, physically disabled individuals are capable of improving physiological variables through training in much the same way of able bodied individuals. 

Conclusion

In summary, it is important to understand the benefits of physical activity for children with a physical disability.  Physiologically these individuals are capable of reaping the benefits of not only a normal exercise program but can excel in sports at the elite level.  Exercise can not only be a physiological benefit but also a psychological benefit as it allows independence.  Considering the subjects in this paper were all children and adolescents, it should be clear why not only participation in physical activity is critical to a growing child but how it can be beneficial.  Future directions may help explain how to better accommodate these children and adolescents and allow them to excel.  Further research should look more at the extent of the disability instead of grouping disabilities together.  One should also realize that physically disabled children are capable of performing, benefiting and excelling in all aspects of physical activity.  

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