PHYS THER
Vol. 86, No. 8, August 2006, p. 1108
M Kathleen Kelly
Field tests of aerobic capacity can provide valid, reliable outcome measurements without the burden of expensive equipment in a sophisticated laboratory setting. To date, however, there are no validated field tests for measuring aerobic fitness in children or adolescents with cerebral palsy (CP), and there is a paucity of exercise test protocols appropriate for children with CP. These authors adapted a commonly used field test—the shuttle run test (SRT)—to accommodate children classified at level I or level II on the Gross Motor Function Classification System (GMFCS). A separate protocol was designed for each level (SRT-1 and SRT-2). The protocols then were compared with a treadmill test that was adapted for children with CP. The authors demonstrated that, in addition to being clinically feasible, the 2 SRTs were reproducible, yielded reliable measurements, and compared favorably with the treadmill test in monitoring changes in exercise capacity.
Children and adolescents with CP who were students at a school for special education and were between the ages of 7 and 20 years were the participants. Participation in the study was limited to those students who were classified at either GMFCS level I (n = 14) or GMFCS level II (n = 11).
Children with CP who are independent with ambulation on level surfaces can participate in standardized field tests designed to assess aerobic capacity. These researchers attempted to develop and validate field tests using the GMFCS levels as a guide to developing the SRT protocols, which added to their clinical utility and feasibility. The SRTs were reproducible, and, when compared with the treadmill protocols, were shown to yield similar measurements of heart rate and exercise time to reach peak oxygen uptake (
o2peak). However, o2peak could only be predicted from sex and body weight and not from any of the treadmill protocol variables (speed, exercise time, or GMFCS level). Thus, the SRTs are appropriate as a way to monitor changes in exercise tolerance over time, but not as an approximation of o2peak.
Because the classic treadmill protocols used to measureo2peak are not appropriate for children with motor impairments, these investigators developed and piloted 2 new treadmill protocols based on the 2 different GMFCS levels (level I or II). The 2 protocols varied with respect to starting speeds, but the incremental increases in speed were the same. The treadmill tests were then used to benchmark the 2 SRT protocols. In order to assess the validity between the 2 tests, all subjects performed 1 SRT and 1 treadmill test in a laboratory setting while wearing a face mask to obtain o2peak and other physiologic variables. To establish the test- retest reliability, a second SRT was performed within 2 weeks of the first (done without the gas analysis).
The study describes the reliability and validity of a standardized way to assess aerobic capacity in a group of children who are at high risk for secondary impairments due to deconditioning. Although it is premature to argue that the adapted shuttle run test protocols are valid field tests to estimateo2peak, their clinical utility and feasibility are reproducible and compare favorably to physiologic measurements obtained during treadmill testing. This work gives physical therapists a method of measuring cardiovascular responses in children at GMFCS level I or II.
As recognized by the authors, the lack of validity data on the treadmill tests was a major limitation. The study results were centered on the SRTs being benchmarked against the "gold standard" treadmill tests—when in fact, the treadmill tests have never been validated for children with CP. Further research is needed to adjust the SRT protocols such thato2peak can be extrapolated. At a minimum, this type of standardized protocol can be used to begin establishing norms for children who are classified at different functional levels (ie, the GMFCS).
Vol. 86, No. 8, August 2006, p. 1108
Research Reports |
The Bottom Line
M Kathleen Kelly, PT, PhD, Assistant Professor & Vice Chair, Department of Physical Therapy, University of Pittsburgh, Pittsburgh, Pa.
What problems did the researchers set out to study, and why?
Field tests of aerobic capacity can provide valid, reliable outcome measurements without the burden of expensive equipment in a sophisticated laboratory setting. To date, however, there are no validated field tests for measuring aerobic fitness in children or adolescents with cerebral palsy (CP), and there is a paucity of exercise test protocols appropriate for children with CP. These authors adapted a commonly used field test—the shuttle run test (SRT)—to accommodate children classified at level I or level II on the Gross Motor Function Classification System (GMFCS). A separate protocol was designed for each level (SRT-1 and SRT-2). The protocols then were compared with a treadmill test that was adapted for children with CP. The authors demonstrated that, in addition to being clinically feasible, the 2 SRTs were reproducible, yielded reliable measurements, and compared favorably with the treadmill test in monitoring changes in exercise capacity.
Who participated in the study?
 TopWhat problems did the... Who participated in the... What new information does...How did the researchers...How might the results...What are the limitations... |
|---|
Children and adolescents with CP who were students at a school for special education and were between the ages of 7 and 20 years were the participants. Participation in the study was limited to those students who were classified at either GMFCS level I (n = 14) or GMFCS level II (n = 11).
What new information does this study offer?
|
TopWhat problems did the...Who participated in the...What new information does...How did the researchers...How might the results...What are the limitations... |
|---|
Children with CP who are independent with ambulation on level surfaces can participate in standardized field tests designed to assess aerobic capacity. These researchers attempted to develop and validate field tests using the GMFCS levels as a guide to developing the SRT protocols, which added to their clinical utility and feasibility. The SRTs were reproducible, and, when compared with the treadmill protocols, were shown to yield similar measurements of heart rate and exercise time to reach peak oxygen uptake (
o2peak). However, o2peak could only be predicted from sex and body weight and not from any of the treadmill protocol variables (speed, exercise time, or GMFCS level). Thus, the SRTs are appropriate as a way to monitor changes in exercise tolerance over time, but not as an approximation of o2peak.
How did the researchers go about the study?
|
TopWhat problems did the...Who participated in the...What new information does...How did the researchers...How might the results...What are the limitations... |
|---|
Because the classic treadmill protocols used to measure
o2peak are not appropriate for children with motor impairments, these investigators developed and piloted 2 new treadmill protocols based on the 2 different GMFCS levels (level I or II). The 2 protocols varied with respect to starting speeds, but the incremental increases in speed were the same. The treadmill tests were then used to benchmark the 2 SRT protocols. In order to assess the validity between the 2 tests, all subjects performed 1 SRT and 1 treadmill test in a laboratory setting while wearing a face mask to obtain o2peak and other physiologic variables. To establish the test- retest reliability, a second SRT was performed within 2 weeks of the first (done without the gas analysis).
How might the results of this study apply to patients who are treated by physical therapists from this point forward?
|
TopWhat problems did the...Who participated in the...What new information does...How did the researchers...How might the results...What are the limitations... |
|---|
The study describes the reliability and validity of a standardized way to assess aerobic capacity in a group of children who are at high risk for secondary impairments due to deconditioning. Although it is premature to argue that the adapted shuttle run test protocols are valid field tests to estimate
o2peak, their clinical utility and feasibility are reproducible and compare favorably to physiologic measurements obtained during treadmill testing. This work gives physical therapists a method of measuring cardiovascular responses in children at GMFCS level I or II.
What are the limitations of the study, and what further research is needed?
|
TopWhat problems did the...Who participated in the...What new information does...How did the researchers...How might the results...What are the limitations... |
|---|
As recognized by the authors, the lack of validity data on the treadmill tests was a major limitation. The study results were centered on the SRTs being benchmarked against the "gold standard" treadmill tests—when in fact, the treadmill tests have never been validated for children with CP. Further research is needed to adjust the SRT protocols such that
o2peak can be extrapolated. At a minimum, this type of standardized protocol can be used to begin establishing norms for children who are classified at different functional levels (ie, the GMFCS). [Verschuren O, Takken T, Ketelaar M, et al. Reliability and validity of data for 2 newly developed shuttle run tests in children with cerebral palsy. Phys Ther. 2006;86:1107–1117.]
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Physical Therapy 2006 86: 1107-1117.
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