Spinal cord injury and congenital paraparesis caused by disorders such as spina bifida result in physical inactivity that is potentially costly in health and economic terms. When the ability to be physically active and mobile is compromised, independence is lost (1
) and emotional well-being is reduced (3
). Regular habitual activity is a missing component of the lives of most persons with disabilities (4
). Coyle and Santiago concluded that physical inactivity was a major contributing factor in the deteriorating physical health of persons with disabilities (5
). Other studies found that a sedentary lifestyle makes ambulation in a wheelchair a more stressful event when fitness levels are low (6–9
). A primary goal of many medical treatments and rehabilitation programs for children and adolescents with disabilities is to restore patients' ability to be physically active.
Improvement in physical fitness through increased physical activity has been shown to be important for health maintenance and disease prevention. Improvement in cardiopulmonary endurance, body composition, muscle strength and endurance, and flexibility are associated with reductions of risk factors for various disease stages. Epidemiological studies in adults suggest that regular physical activity contributes to longevity and decreases the risk of death from a variety of causes (10–13
). With respect to cardiovascular heart disease, inactivity has been shown to be the second most costly risk factor (14
). Physical activity is associated most strongly with the prevention and control of coronary artery disease (16
), hypertension (17
) non–insulin-dependent diabetes mellitus, (19
), osteoporosis (20
), obesity (22
), and mental health problems (23–28
In recent years, the Centers for Disease Control and Prevention (29
), the American College of Sports Medicine (ACSM) (30
), the US Public Health Service (31
), the National Institutes of Health (32
), the US Department of Health and Human Service (2
), and the American Heart Association (33
) have all published recommendations for increased physical activity based on health concerns and minimum guidelines for exercise and activity. Recently, the ACSM pointed out that the quantity and quality of exercise needed to attain health-related benefits may differ from what is recommended for fitness benefits. Research now indicates that lower levels of physical activity (particularly with reference to intensity) confer significant health-related benefits to sedentary persons (30
The most recent (June 1998) position statement by ACSM regarding the recommended quantity and quality of exercise represents the latest synthesis of research knowledge in this area (30
). In comparison with the previous ACSM position statement released in 1990 (34
), the current statement modifies the recommendations to accommodate sedentary individuals at low fitness levels. The ACSM position recommends the following minimum standards for aerobic exercise for sedentary individuals: (a) frequency of training: 3 d/wk; (b) duration of training: 20 minutes total, with minimum bouts of no less than 10 minutes; and (c) intensity of training: at least 50% of maximum oxygen uptake reserve (Vo2
R) or 50% of maximum heart rate reserve (HRR). Many studies have correlated this intensity level with a Rating of Perceived Exertion (RPE) of 12 to 14 (30
In 1999, Gater and Ugalde (35
) reviewed several studies incorporating upper extremity aerobic exercise in individuals with paraplegia and tetraplegia. Although many of the studies found that various aerobic exercise protocols using arm crank ergometry, wheelchair ergometry, or wheeling on a track improved aerobic capacity, power output, or both, the most appropriate dosing for this population with regard to intensity, duration, and frequency remains unclear. However, based on their evaluation of the studies and in response to the 1995 Joint Centers for Disease Control/ACSM (36–38
) recommendation that “every US adult should accumulate 30 minutes or more of moderate physical activity on most, preferably all, days of the week,” the authors suggested 20 to 60 minutes at an exercise intensity of about 12 to 13 (somewhat hard) on the Borg Rating of Perceived Exertion scale (RPE), preceded and followed by a 10-minute warm-up/cool-down. They go on to say that “the most important consideration in creating an exercise prescription is patient compliance (and) the most important factors in extended exercise compliance are that the activity be ‘enjoyable and employable’.”
Available options for aerobic exercise using only the upper body have significant limitations for populations with paraparesis and other mobility impairments. Hand cycles, for instance, are fairly large and expensive and can be used only in very specific locations (ie, a paved path with no automobile traffic, sharp turns, or steep hills). Weather is a consideration for individuals living in northern climates. Depending on the user's level of function, a user may require assistance to transfer in and out of the cycle, significantly impacting safety and independence. Tabletop arm ergometers are much smaller, cheaper, and require little assistance to access, but can be quite boring, decreasing compliance.
A new product available seeks to satisfy adolescents' need for enjoyment from exercise by integrating computer video game challenge and aerobic exercise. The GameCycle (Three Rivers Ltd, Mesa, AZ) combines the crank mechanism from a hand cycle with a commercially available game system (GameCube; Nintendo Co., Ltd, Kyoto, Japan) to play a car racing game (Need for Speed II; EA Games, Redwood City, CA). The user cranks the handles to control the speed of the car in the video game. Direction is controlled by tilting the crank handles, similar to steering a hand cycle. The crank resistance can be altered to increase the work required, and crank speed can be calibrated to increase the aerobic effort.
Preliminary experimental results using an early version of the GameCycle indicate that users can experience aerobic training effects with the GameCycle and find the product fun and motivating (39
). Fitzgerald et al (39
) tested and surveyed a select group of wheelchair athletes using the GameCycle with and without the video game. All participants believed that the GameCycle would help to motivate manual wheelchair users to exercise, and 77% of the participants stated that the GameCycle would aid in the frequency and motivation of their own exercise habits.
The purposes of this study were to (a) determine if the GameCycle requires sufficient effort, as outlined by the ACSM, to induce an aerobic training effect and (b) to assess the effectiveness, practicality, and satisfaction of the GameCycle as part of a 4-month, home-based exercise intervention for adolescents with lower extremity mobility impairments caused by spinal cord dysfunction.