The Steep Ramp Test in Children and Adolescents: Norm Values in Relation to Sex and Age

This study aims to generate norm values for healthy children and adolescents,
aged 8 to 18 years, for the Steep Ramp Test. An inventory of commonly used
fitness tests for children (4 to 18 years of age) by 'TNO Kwaliteit van Leven'
shows that there are hardly any norm values for fitness tests and that the
available norm values often were established ~20 years ago. Recently, Dutch
norm values were published for Dutch children, aged 4 to 13 years, for the
Bruce treadmill protocol. However, not all children are able to complete this
test appropriately. Moreover, the use of this test requires a treadmill with a
large slope angle, which is often not available in a physiotherapy practice.
Norm values for a simple, minimally demanding test, which gives a valid and
reliable estimate of the aerobic capacity of children and adolescents, are not
available thus far. The commonly used Astrand test is not validated for
chronically diseased children and neither there are norm values available for
children and adolescents aged 8-18 years. This makes it difficult for
(pediatric) physiotherapists to determine the aerobic fitness of (chronically
diseased) children. Nevertheless, there is a growing interest among
physiotherapists to determine the aerobic fitness of children. Specifically,
there is a growing interest towards the Steep Ramp Test, due to the limited
time required to complete the test, the relatively low costs of material, and
its good reproducibility. The Steep Ramp Test is a steep graded (25Watt/10
seconds) maximum exercise protocol on a bicycle, which continues until
voluntary exhaustion of the participant. The maximal achieved work rate (Wpeak)
is the most important and easy to measure test outcome. However, there is a
lack of norm values for this test for children, adolescents, and adults. The
current study proposes to collect norm values for the Steep Ramp Test in
children and adolescents (part 1 of this study) and to assess the validity and
reproducibility of this test (part 2 of this study).

Primary objective:
- Collecting and setting up norm values for the Steep Ramp Test for healthy
children and adolescents between 8 and 18 years (what is the maximal attained
work rate (Wpeak) during the Steep Ramp Test in healthy children and
adolescents between 8 and 18 years?)

Secondary objectives:
- Determine the validity of the Steep Ramp Test with respect to the maximal
cardiopulmonary exercise test (comparing the attained VO2peak on both tests and
determine the relation between the VO2peak attained during the maximal
cardiopulmonary exercise test and the Wpeak attained during the Steep Ramp Test
within a subgroup of 30 healthy children and adolescents, with a period of 7 to
14 days between two tests)
- Determine the reproducibility of the Steep Ramp Test (period of 7 to 14 days
between two Steep Ramp Tests within a subgroup of 30 healthy children and
adolescents)
- Determine the relation between the Wpeak attained during the Steep Ramp Test
and different growth parameters
- Determine the relation between the Wpeak attained during the Steep Ramp Test
and the objectively measured physical activity (activity monitor)

In part 1 of this study, healthy children and adolescents will participate in a
single Steep Ramp Test on their own primary or secondary school. Before the
start of the study, participants obtain a 'pre-test questionnaire' that will
have to be filled out by their parents. Several demographic variables will be
collected when the child will be tested, like age, ethnicity, and sex.
Moreover, different anthropometric variables will be measured, such as height,
weight, sitting height, and skin folds. Hereafter, children and adolescents
complete a Steep Ramp Test on a bicycle in which the work rate increases in a
relatively fast manner (25Watt/10 sec) until voluntary exhaustion of the
participant. Respiratory gas analysis and volume measurements take place during
the Steep Ramp Test using a mobile and light metabolic test system (Cortex
Metamax B3, Cortex Medical GmbH, Leipzig, Germany), which is easy to put on and
not unpleasant to wear. The metabolic test system consist out of a measuring
unit, which should be carried on the chest, a HR belt, which should be placed
around the chest, and a facemask. The equipment has a wireless connection with
a computer, so real-time physical strain (minute ventilation, oxygen uptake,
carbon dioxide production, and heart rate) of the children during the Steep
Ramp Test can be measured. Before and directly after the Steep Ramp Test the
participants will be asked to fill out a OMNI-scale concerning the rate of
perceived exertion. Moreover, physical activity in daily life will be monitored
by accelerometry. Each participant obtains an advanced accelerometer
(Actigraph) in order to measure their daily level of activities continiously
during one week. Participants have to attach the accelerometer around their hip
and will be asked to keep track of their daily activities using an activity
diary.

Based on these data, norm values will be set up using advanced statistical
modelling, Generalized Additive Models for Location, Scale and Shape (GAMLSS).
This method is an extension of the LMS method. GAMLSS are (semi)parametric
regression models, who use different types of distributions in order to find
the best distribution of the data.

In part 2 of this study, we will examine the validity of the Steep Ramp Test in
a small subgroup of 30 participants. Next to the Steep Ramp Test of part 1,
this subgroup will perform a maximal cardiopulmonary exercise test on a bicycle
with respiratory gas analysis within a period of 7 to 14 days after the Steep
Ramp Test. Peak oxygen uptake (VO2peak) obtained during the Steep Ramp Test
will be compared with the VO2peak obtained during the maximal cardiopulmonary
exercise test and additionally the relation between the VO2peak attained
during the maximal cardiopulmonary exercise test and the Wpeak attained during
the Steep Ramp Test will be determined.

Additionally, we will examine the reproducibility of the Steep Ramp Test in a
small subgroup of 30 participants. Next to the Steep Ramp Test of part 1, this
subgroup will perform a second Steep Ramp Test on a bicycle with respiratory
gas analysis within a period of 7 to 14 days after the first Steep Ramp Test.

In part 1, the participants will be asked to perform a single Steep Ramp Test
with respiratory gas analysis until voluntary exhaustion. The activity pattern
of children in daily life consists out of short burst of intense exercise and
since we include only healthy children and adolescents, we expect the burden
and risks associated with this study to be minimal. The Steep Ramp Test
includes a small risk. The heart muscle will be more burdened then normal,
which sporadically causes complications. The risk for heart attack during the
Steep Ramp Test is very small. The risk for arrhythmias is somewhat higher,
however, the risks are almost negligible. Before and directly after the Steep
Ramp Test the participants will be asked to fill out a OMNI-scale concerning
the rate of perceived exertion. The demographic and anthropometric measurements
do not include risks either. The study will take place in the primary or
secondary school of the participant and the total time associated with the
participation in part 1 of this study includes only 30 minutes. Wearing the
advanced accelerometer for one week is not included within these 30 minutes.
Filling out the activity diary only requires 5 minuter a day.

Participants who are also willing to take part in part 2 of this study will
have to perform a second Steep Ramp Test or a normal maximal exercise test with
respiratory gas analysis until voluntary exhaustion. Maximal exercise testing
(Steep Ramp Test as well as a normal maximal exercise test) includes a small
risk. The heart muscle will be more burdened then normal, which sporadically
causes complications. The risk for heart attack during the maximal exercise
test is very small. The risk for arrhythmias is somewhat higher, however, the
risks are almost negligible. Before and directly after the Steep Ramp Test the
participants will be asked to fill out a OMNI-scale concerning the rate of
perceived exertion. Part 2 of the study will take place in the primary or
secondary school of the participant and the total time associated with the
participation in part 2 of this study includes only 30 minutes.