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 (14,15). Physical activity is associated most strongly with the prevention and control of coronary artery disease (16), hypertension (17,18) non–insulin-dependent diabetes mellitus, (19), osteoporosis (20,21), 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 (Vo₂R) 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.

Before the 16-week home training program, 6 of the 8 subjects reached a Vo₂ of at least 50% of their Vo₂ reserve while cranking the GameCycle (Figure 2), the level recommended by the ACSM to be sufficient to induce a training effect. Seven of the 8 subjects reached a HR of at least 50% of their HRR (Figure 3). Only 1 subject did not reach the 50% level for either HRR or Vo₂R. All subjects reached an RPE level of at least 12 (Figure 4).

After completing the 16-week home-training program, 6 of the 8 subjects substantially increased the work they were able to achieve during the maximal arm crank ergometer test (Table 1) and the mean maximum work achieved by the group significantly increased from 65.5 ± 9.7 to 77.7 ± 7.1 W (P < 0.015). One individual only increased by 1.6%, and 1 subject showed a decrease of 4.8%. The 2 subjects who showed the least amount of improvement or no improvement had the highest initial values for strength and aerobic capacity during the pretest evaluation. Overall, the amount of aerobic improvement was inversely correlated (r = −0.60) with initial elbow flexion strength.

Analysis of the HR during the GameCycle monitoring was not feasible because of an excessive amount of missing data. Large amounts of data were missing because the subjects either forgot to put on the HRM when playing the GameCycle, did not start the recording correctly, or had technical problems from electromagnetic interference. Because of these difficulties, it was necessary to rely on the verbal reports of the subjects and their parents regarding HR targets and compliance.

Most of the subjects reported that they completed the exercises as directed and were able to reach their target HR. All but one subject felt the GameCycle was physically challenging enough to reach their target training zone. Most subjects (69%) agreed that the GameCycle would help motivate them to exercise more often and for longer periods of time. Most of the negative responses were related to the size and weight of the GameCycle frame. Most of the subjects (92%) agreed that the GameCycle was easy to use, enjoyable, motivating, and comfortable (Figure 5).

The 2 subjects who did not reach the ACSM guidelines for Vo₂ had the highest baseline strength values (Table 2) and had well-developed shoulder, arm, and chest musculature. These individuals also had the lowest percent increases in maximum power output after 4 months of training. One of these 2 subjects also reported that the GameCycle was not physically challenging despite having the GameCycle set at the highest resistance level during the intervention. This illustrates a possible shortcoming of the GameCycle as an aerobic exercise modality for adults or adolescents with well-developed upper bodies. In these populations, a higher initial GameCycle setting and/or longer duration of exercise may enable them to experience greater aerobic training effects. Further exploration in faster crank speeds is needed, as well as energy consumption during actual game play. In contrast, those individuals with weaker initial strength values and lower cardiorespiratory fitness measurements exhibited a steeper increase in HR and Vo₂ with increasing resistance levels and showed a greater improvement in maximum power output on the arm crank ergometer over 16 weeks of training. This is a common phenomenon seen in many exercise intervention studies (ie, those subjects with the lowest initial fitness measures show the greatest initial improvement over baseline).

Although the size of the subject group was small, and compliance was ascertained by self-report and parent-report, which limit the conclusions taken from these data, these preliminary results show excellent promise for the GameCycle as a viable exercise alternative to the limited options available to adolescents with mobility impairment. Currently, the GameCycle is not widely available and is cost-prohibitive for many families. As with most technology, costs and availability may improve rapidly over time. The GameCycle has other benefits beyond an exercise modality. It is entertaining and can be used by all family members (with additional ports for competitive gaming). Thus, there may be benefits in terms of increased socialization and reduced isolation. Future studies should include subjects groups with greater numbers and diversity.