Reference values for the Muscle Power Sprint Test (MPST) in children from the age of 5 up to and including 12 years

Children with birth defects - including congenital diaphragmatic hernia,
congenital lung abnormalities, and congenital heart disease - are at risk for
below-average lung function and exercise tolerance (1-3). This is one of the
reasons why, at our tertiary hospital, children with congenital abnormalities
are enrolled in a prospective, longitudinal follow-up program from birth as a
part of standard care (4). This program involves outpatient visits at preset
intervals during which the overall health and development of these patients are
examined. They also undergo spirometry and tests with pediatric
physiotherapists to assess their exercise tolerance. In the past, we used the
Bruce protocol as the exercise test of choice for children aged 5 and above.
This test involves walking on a treadmill with an incline - with increasing
gradient and speed - until the subjects can no longer continue (8). The Bruce
protocol comes with several limitations. Firstly, the steep incline of the
treadmill (> 10%) demands a lot of muscle power in the thighs, which patients
with congenital conditions may not always be able to develop. Secondly,
workload increases in large increments with each sequential step of the Bruce
protocol which may force children to stop before reaching their peak oxygen
uptake (5). The two aforementioned limitations could also trigger anxiety in
the subjects, potentially leading to premature discontinuation of the Bruce
protocol and thus reducing reliability of results. In the newer versions of the
longitudinal follow-up program, the Bruce protocol was therefore replaced by
other exercise tolerance tests, including the Muscle Power Sprint Test (MPST).
In contrast to the Bruce protocol - testing aerobic capacity - the MPST is
designed to assess anaerobic exercise capacity, which is important for young
children to participate in daily activities such as playing with peers (6). The
test is administered by having children sprint six times over a distance of
fifteen meters, with a ten-second rest between each sprint. Using the formula
"power = (total mass x 15 m²)/time³ ", the force generated during each sprint
can be calculated (9). The average power of the six sprints is typically the
measure that is reported and is presented as *mean power*. Dutch norm values
for children aged 6-18 have been established with data gathered between 2012
and 2016, mainly in rural areas in the Netherlands (10). Due to the ongoing
changes in the lifestyles of children and their environments, regularly
updating reference values regarding exercise tolerance is essential. This is
especially pertinent in light of the recent Covid-19 pandemic, which has
contributed to a reduction in physical activity and the adoption of more
sedentary lifestyles (7). Additionally, there are currently no established
reference values for children aged 5, who undergo testing using the MPST in the
light if our longitudinal follow-up program. Consequently, we lack comparative
data for the results of their exercise tolerance tests at this time. 1. Hijkoop
A, van Schoonhoven MM, van Rosmalen J, Tibboel D, van der Cammen-van Zijp MHM,
Pijnenburg MW, et al. Lung function, exercise tolerance, and physical growth of
children with congenital lung malformations at 8 years of age. Pediatr
Pulmonol. 2019;54(8):1326-34. 2. Schaan CW, Macedo ACP, Sbruzzi G, Umpierre D,
Schaan BD, Pellanda LC. Functional Capacity in Congenital Heart Disease: A
Systematic Review and Meta-Analysis. Arq Bras Cardiol. 2017;109(4):357-67. 3.
Toussaint-Duyster LCC, van der Cammen-van Zijp MHM, de Jongste JC, Tibboel D,
Wijnen RMH, Gischler SJ, et al. Congenital diaphragmatic hernia and exercise
capacity, a longitudinal evaluation. Pediatr Pulmonol. 2019;54(5):628-36. 4.
Gischler SJ, Mazer P, Duivenvoorden HJ, van Dijk M, Bax NM, Hazebroek FW, et
al. Interdisciplinary structural follow-up of surgical newborns: a prospective
evaluation. J Pediatr Surg. 2009;44(7):1382-9. 5. Fredriksen PM, Ingjer F,
Nystad W, Thaulow E. Aerobic endurance testing of children and adolescents--a
comparison of two treadmill-protocols. Scand J Med Sci Sports. 1998;8(4):203-7.
6. Bailey RC, Olson J, Pepper SL, Porszasz J, Barstow TJ, Cooper DM. The level
and tempo of children's physical activities: an observational study. Med Sci
Sports Exerc. 1995;27(7):1033-41. 7. Stephanie S, Mike T, Mark T, Jae S, Yvonne
B, Laurie B, et al. Changes in physical activity and sedentary behaviours from
before to during the COVID-19 pandemic lockdown: a systematic review. BMJ Open
Sport & Exercise Medicine. 2021;7(1):e000960. 8. van der Cammen-van Zijp MH,
Ijsselstijn H, Takken T, Willemsen SP, Tibboel D, Stam HJ, et al. Exercise
testing of pre-school children using the Bruce treadmill protocol: new
reference values. Eur J Appl Physiol. 2010;108(2):393-9. 9. Verschuren O,
Takken T. The muscle power sprint test. J Physiother. 2014;60(4):239. 10.
Steenman K, Verschuren O, Rameckers E, Douma-van Riet D, Takken T. Extended
Reference Values for the Muscle Power Sprint Test in 6- to 18-Year-Old
Children. Pediatr Phys Ther. 2016;28(1):78-84.

Our primary goal is to establish generalizable reference values for the MPST in
Dutch primary school children aged 5 up to and including 12 years.

The study adopts a prospective cross-sectional design, as new data regarding
anaerobic performance is generated at a single time-point. The intervention
involves administering the MPST to children from the age of 5 up to and
including 12 years in collaboration with primary schools and after-school
childcare centers. This design allows for the simultaneous assessment of
different age groups.

The Muscle Power Sprint Test (MPST) is an easy to perform field test of
anaerobic capacity for children and adolescents. The only necessities for
administration of this test are an open space, a stopwatch and two cones or
lines. Test subjects are instructed to perform six 15m-sprints at maximum pace
between the two cones / lines, with a 10-second rest in between each effort.
The power that is generated with each sprint can be calculated using the
formula: power = (total mass x 15 m²)/time³.

We estimate that the risk of injuries or other adverse effects from
participation is not higher than the risks a child might encounter in a typical
physical education class; on the contrary, we believe it is lower.