One of the first investigators to assess the cardiorespiratory fitness levels of persons with cerebral palsy was the Swedish physiologist, Ake Lundberg. The aim of one of Lundberg's earlier studies was to determine the maximal aerobic power of persons with spastic cerebral palsy. Lundberg measured the aerobic power of nine children and five young men with spastic diplegia. Nine children without disabilities and five men without disabilities served as the control group. The degree of disability ranged from slight (no aids to ambulate) to severe (six of the 14 subjects used a wheelchair). All tests were performed on a mechanically braked bicycle ergometer. Results showed that the subjects with cerebral palsy had lower values for heart rate, oxygen uptake, ventilation, and blood lactate concentrations compared to the control group. Physical work capacity at 170 beats per minute was only 50 percent of the non-disabled controls.
In a later study, Lundberg examined longitudinally the physical work capacity and aerobic power in 19 children with spastic diplegia, and compared them to a control group of 12 non-disabled children of the same age and sex. The degree of impairment ranged from slight (no aids required to ambulate, six boys and three girls) to fairly severe (six boys and four girls, eight of whom used a wheelchair). Heart rate, oxygen consumption (VO2), physical work capacity at heart rate 170, pulmonary ventilation, and blood lactate concentrations were measured during submaximal and maximal work on a bicycle ergometer two or three times a year over a six-year period. Levels of fitness (VO2 and physical work capacity) were higher for the control group compared to subjects with cerebral palsy, but over the six-year period this gap did not increase. Interestingly, absolute values for aerobic power and physical work capacity increased from 12 to 18 years in both groups.
In 1990, Fernandez, Pitetti and Betzen evaluated the aerobic capacity of nine ambulatory adults with spastic cerebral palsy and concluded that their cardiorespiratory fitness levels were very poor.
As a follow up to this research, Pitetti et al. developed a cardiorespiratory conditioning program for seven ambulatory adults with spastic cerebral palsy to try to improve their functional capacity (peak VO2). A secondary purpose of the study was to determine if after an 8-week training program, subjects would continue to exercise on their own. Subjects exercised on a Schwinn Air-Dyne bicycle ergometer twice a week for 30 minutes at a work intensity between 40 to 70% of peak VO2. Significant improvements in peak VO2 were achieved at the end of the 8-week program (average improvement was 12%).
The researchers concluded that cardiorespiratory fitness improved in seven adults with cerebral palsy who trained on a Schwinn Air-Dyne for eight weeks. However, once the study ended, only one subject continued to exercise. When developing exercise programs for persons with cerebral palsy, it is important to consider the barriers to exercise and determinants of exercise in this population. The best exercise guidelines in the world will have little impact if substantial barriers (i.e., transportation, cost, medical concerns, etc.) cannot be overcome. However, once the study ended, only one adult continued to exercise. The investigators concluded that the cardiorespiratory fitness levels of adults with cerebral palsy were very low, and suggested a strong need for further research to determine the most appropriate training regimens for improving cardiorespiratory fitness in this population.