International  Journal  of
Environmental Research
and Public Health
Article
Participation and Performance Analysis in Children
and Adolescents Competing in Time-Limited
Ultra-Endurance Running Events
Volker Scheer 1,2
, Stefania Di Gangi 3, Elias Villiger 3
, Thomas Rosemann 3,
Pantelis T. Nikolaidis 4
and Beat Knechtle 3,5,*
1
Ultra Sports Science Foundation, 69130 Pierre-Bénite, France; volkerscheer@yahoo.com
2
Health Science Department, Universidad a Distancia de Madrid (UDIMA),
28400 Collado Villaba, Madrid, Spain
3
Institute of Primary Care, University of Zurich, 8091 Zürich, Switzerland; Stefania.DiGangi@usz.ch (S.D.G.);
evilliger@gmail.com (E.V.); thomas.rosemann@usz.ch (T.R.)
4
Exercise Physiology Laboratory, 18450 Nikaia, Greece; pademil@hotmail.com
5
Medbase St. Gallen Am Vadianplatz, 9001 St. Gallen, Switzerland
*
Correspondence: beat.knechtle@hispeed.ch; Tel.: +41-71-226-93-00
Received: 8 February 2020; Accepted: 29 February 2020; Published: 3 March 2020


Abstract: Ultra-endurance running is of increasing popularity in the adult population, mainly due to
master runners older than 35 years of age. However, youth runners younger than 19 years of age are
also competing in ultra-endurance events, and an increase has been observed in distance-limited
events, but no data is available on time-limited ultra-endurance events in this age group. This study
investigated participation and performance trends in time-limited ultra-endurance races, including
multi-day events, in runners younger than 19 years of age. Between the period 1990 and 2018,
the most popular events recorded a total of 214 ﬁnishes (from 166 unique ﬁnishers (UF)) for 6-h
events, 247 (212 UF) for 12-h events, and 805 (582 UF) for 24-h events, respectively. The majority of
athletes originated from Europe and North America. Only a minority participated in multi-day events.
Overall, speed increased with age, but the overall performance speed decreased across calendar years
for 6- and 24-h events as participation numbers grew. In summary, in youth ultra-endurance runners,
diﬀerences were observed regarding participation and performance across the diﬀerent time-limited
events, the age of the athletes and their country of origin
Keywords: boy; girl; ultra-endurance; running; ultramarathon
1. Introduction
Ultra-endurance running can be deﬁned as running activities lasting longer than six hours [1–3].
These activities can be distance- or time-based, with typical time-based ultra-endurance events ranging
from six hours to several days, the distance covered during this time period being recorded and ranked
among competitors [4]. Popular time-based events in the adult population include races over 24 h
and participation numbers have increased over the years, particularly among master athletes and
women [3,5]. Men are generally faster than women, however, women have closed the gap in the last
decade [6]. Most adult ultra-endurance athletes in 24-h events originate from Europe, mostly France
and Germany [6]. Multi-day ultra-endurance events are also quite popular, with an exponential increase
between the 1990s and 2010 [7]; however, competitor numbers are generally lower compared to other
ultra-endurance races. Again, most ﬁnishers come from Europe, mainly France, the United Kingdom
and Germany, followed by runners from the USA, Asia, Africa, Australia and South America [7].
Ultra-endurance races can be held in challenging and remote environments, and can include races in
Int. J. Environ. Res. Public Health 2020, 17, 1628; doi:10.3390/ijerph17051628
www.mdpi.com/journal/ijerph
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the heat, desert, cold or jungle environments [3,8–11]. Peak running performance has increased with
increasing event duration in races lasting from hours to ten days in adults [4].
As outlined, the participation and performance trends of ultra-endurance running are well
described in the adult population [12,13], as well as the performance diﬀerences among sexes [14,15];
however, very little is known about childhood participation in ultra-endurance running events and if,
indeed, they should be participating in them at all [16]. For ultra-marathons, mainly the aspects of
age [4,17] and nationality [18,19] have been investigated. One concern is that running and training for
ultra-endurance distances at a young age can have acute negative eﬀects on an immature or developing
muscular skeletal system or another organ system. Other concerns may relate to the long-term negative
health eﬀects this could have; however, this is currently not known and has not been investigated [15].
Until recently there was only anecdotal evidence that children and adolescents participate in
ultra-endurance events; however, one study was able to demonstrate that the participation of children
and adolescents younger than 19 years old is a reality [3]. This study looked at participation trends
among youth ultramarathon runners and described an exponential increase in participation in the
last 20 years [16]. The most popular race distances were those of 100 km, followed by 50 km and
50 miles, with the majority of ﬁnishers being older boys between 16–18 years of age [20]. However,
ultramarathon running is only distance based, deﬁned as races over marathon distance (42.195 km),
and is quite distinct to time-based or multi-day events. Youth ultra-endurance athletes ﬁrst participated
in multi-day events in the year 2000, with events ranging from two to eight days, with distances
covering 81 to 293 km, respectively; however, less than 50 runners participated in these events in the
last two decades [20].
To date, there are no data available on the country of origin of the ultra-endurance youth
participants and similarly no data are available on their performance times. This is the ﬁrst study
examining participation and performances in time-limited ultra-endurance and multi-day events
in youth runners. This is of practical interest to scientists, coaches and health care professionals,
looking after youth ultra-endurance runners, to get a better understanding of participation trends
and performance times. Our aim was, therefore, to examine participation numbers and trends,
including countries of origin, race performance times and speeds and sex diﬀerences, in children and
adolescents younger than 19 years of age in time-based ultra-endurance and multi-day running events.
Our hypothesis was that participation numbers would increase over calendar years and in time, more
boys than girls would participate in these events, and that the performance times from boys would
be faster.
2. Materials and Methods
2.1. Ethical Approval
The study was approved by the medical council (Ärztekammer Westfalen Lippe, Germany) and
the University of Münster, Germany (Chairperson Prof Berdel, protocol number 2018-304-f-S).
2.2. Data Sampling and Data Analysis
All data were obtained from the Deutsche Ultramarathon Vereinigung (DUV) website where all
the race results of ultramarathons are recorded (https://statistik.d-u-v.org/index.php). The DUV is the
largest ultra-running database worldwide, containing more than 5.8 million performances of more
than 1.4 million runners in approximately 60,000 ultramarathon events and is widely used to gain
insights in participation and performance trends in ultra-running (www.ultra-marathon.org/) [3,16,17].
A computer script was written to retrieve a list for every event recorded on the website. Each event’s
web page was then read by the script to extract the complete data table available. The script compiled
all that data into one large Excel ﬁle, which was our starting point for further manual ﬁltering of
relevant information. We extracted data of time-limited races (i.e., 6, 8, 12, 24, 48, 72 h, 6 and 8 days)
from 1990 to 2018.
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The following variables were extracted: year of race, race distance/duration, name of the race,
race performance (km or miles), name of athlete, year of birth, nationality of athlete, and sex of athlete.
Running speed (km/h) was calculated from the performance and duration variables. Age was obtained
by subtracting the year of birth from the year when the race was held. Continent variable was deﬁned
from the nationality of the athletes.
2.3. Statistical Analysis
The outcome was the running speed (km/h). Information for all races: number of observations,
mean (SD) and minimum and maximum of speed (km/h) is provided in Table 1. For the main
analyses, time-limited races of 8, 48, 72 h, 6 and 8 days were excluded due to insuﬃcient data (< 100
observations). Descriptive statistics were presented as means (SD = standard deviations) by sex,
age groups, continents and time groups. The age groups were 10–13, 14–15, 16–17 and 18 years.
The continent groups, with reference to the nationality of the athletes, were: Africa, Asia, Central-South
America, Europe, North-America, Oceania. When the number of observations of each continent group,
within each race, was not greater than ten, continents were grouped together into other continents.
To show a performance by a period of time, the calendar year of the race was grouped into time
periods of 10 years. Age and calendar year were considered as continuous variables, in 1-year intervals,
when deﬁned as predictor variables for ultra-running speed. In fact, non-linear regression mixed
models, with basis splines (BS), were performed to examine the time trend together with the eﬀects
of sex, age and continent on the speed time of each duration race. The mixed models were used to
correct repeated measurements within runners (clusters) through the random eﬀects of intercepts.
The statistical models were speciﬁed as follows:
Ultra-running speed (Y) ~ [Fixed eﬀects (X) = BS(Year, df = 3) + BS(Age, df = 3) *sex + continent +
[random eﬀects of intercept=runners]
where BS(Year, df=3) and BS(Age, df = 3) are three degrees of freedom (df) basis splines changing with
calendar year and age, respectively; BS(Age, df = 3) * sex denote the age–sex interaction term. Diﬀerent
analyses were performed, one for each duration (6, 12, and 24 h). The interaction term age–sex was
signiﬁcant and considered only in the 24-h events. In the 6- and 12-h race analyses, a linear term on
year, instead of a spline term, was considered. Results of the regression models were presented as
estimates and standard errors. Statistical signiﬁcance was deﬁned as p < 0.05. All statistical analyses
were carried out with R, R Core Team (2016). R: A language and environment for statistical computing.
R Foundation for Statistical Computing, Vienna, Austria. URL https://www.R-project.org/. The R
packages ggplot2, lme4, and lmerTest were used, respectively, for data visualization and for the mixed
models.
Table 1. Ultra-endurance performance—speed km/h by duration. Mean (SD) and minimum (Min),
maximum (Max) were reported.
Duration
Running Speed (km/h)
N
Mean (SD)
Min
Max
6 h
214
8.84 (1.06)
7.50
12.83
8 h
68
6.97 (0.92)
5.68
10.24
12 h
247
5.39 (1.36)
3.75
10.42
24 h
805
2.83 (1.00)
1.87
8.00
48 h
46
2.40 (1.06)
0.94
4.37
72 h
50
1.54 (0.72)
0.66
3.24
6 days
13
1.57 (0.77)
0.45
3.37
8 days
7
1.72 (0.35)
1.15
2.30
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3. Results
Between 1990 and 2018, the total number of observations, over 6-, 12- and 24-h races was n = 214,
n = 247, and n = 805 records, respectively. Instead, the number of individual ﬁnishers was, respectively,
n = 166, n = 212 and n = 582. We observed that the percentage of children aged 10–13 years was
relatively high. In fact, in 24-h races, the majority were 10–13 years, 376 (46.7%). Instead, in 6-h races,
the majority of ﬁnishers, 81 (37.9%), were 18 years and in the 12-h race, the majority were 16-17 years,
83 (33.6%).
In the 6- and 24-h races, 146 (68.2%) and 441 (54.8%), respectively, came from Europe but in the
12-h races, the majority of 130 (52.6%) came from North America. In time-limited races, however,
no participation was recorded before 1990 and the vast majority participated within the last 8 years.
The number of observations and the average performance by sex, age groups, continent and time
groups are reported for distance races, respectively, in Table 2. In Figures 1–3, the participation (%) and
average performances (km/h) by nationality for each time-limited race are reported. Table 3 describes
the results of the statistical models, as described in the methods section. Boys were signiﬁcantly faster
than girls only in the 12-h race. There were no signiﬁcant diﬀerences between North America, Europe
and other continents.
Table 2. Mean ultra-endurance running speed in km/h and (SD): duration of races (6, 12 and 24 h) by
sex, age, country (continent) and calendar year groups. Africa, Asia, Central-South America, Oceania,
due to small sample size, were combined into “Other” group.
Duration
6 h, N = 214
12 h, N = 247
24 h, N = 805
Age
Sex
N
Mean (SD)
N
Mean (SD)
N
Mean (SD)
10–13
F
5
8.23 (0.34)
24
4.94 (0.93)
136
2.45 (0.56)
M
18
8.16 (0.51)
22
5.05 (0.98)
240
2.53 (0.77)
14–15
F
7
8.68 (0.66)
18
4.91 (1.10)
84
2.84 (0.89)
M
32
8.47 (0.93)
36
5.01 (1.10)
101
2.93 (0.86)
16–17
F
17
8.52 (0.91)
23
5.21 (1.08)
55
2.83 (0.94)
M
54
8.82 (0.91)
60
5.34 (1.32)
104
2.97 (0.93)
18
F
20
9.09 (0.78)
17
5.35 (0.80)
26
3.19 (1.01)
M
61
9.33 (1.31)
47
6.42 (1.79)
86
3.85 (1.56)
Continent
Sex
N
Mean (SD)
N
Mean (SD)
N
Mean (SD)
North America
F
11
8.65 (0.96)
53
5.11 (1.02)
106
2.90 (0.94)
M
50
8.71 (0.91)
77
5.51 (1.34)
246
3.03 (1.07)
Europe
F
35
8.77 (0.81)
25
5.07 (0.98)
162
2.50 (0.63)
M
111
8.96 (1.20)
68
5.54 (1.70)
279
2.77 (1.08)
Other
F
M
3
4
8.87 (0.75)
8.22 (0.53)
4
20
5.02 (0.79)
5.62 (1.43)
6
6
3.60 (0.95)
4.21 (0.71)
Year
Sex
N
Mean (SD)
N
Mean (SD)
N
Mean (SD)
1990–1999
F
1
8.77
1
5.00
2
3.10 (0.57)
M
8
9.64 (1.26)
6
6.92 (2.10)
17
4.03 (1.79)
2000–2009
F
19
8.87 (0.77)
16
4.76 (0.97)
23
3.26 (1.05)
M
52
8.99 (1.26)
43
5.35 (1.69)
69
3.50 (1.52)
2010–2018
F
29
8.67 (0.88)
65
5.18 (0.99)
248
2.61 (0.75)
M
105
8.75 (1.00)
116
5.53 (1.36)
439
2.73 (0.82)
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Figure 1. Participation (%) and average performance (km/h) by nationality in 6-h races.
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Figure 2. Participation (%) and average performance (km/h) by nationality in 12-h races.
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Figure 3. Participation (%) and average performance (km/h) by nationality in 24-h races.
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Table 3. Regression analysis (mixed model) of ultra-endurance events (6, 12 and 24 h). Estimates and
standard errors (SE) of ﬁxed eﬀects are reported. p-values ranges are marked with asterisks (see note).
Smoothing terms, basis splines (BS), are denoted with BS(x) t, where x = year, age; t = 1,2,3.
Predictor
Time-Limited Races
6 h
12 h
24 h
Age
BS(Age)1
0.842 (0.940)
1.423 (1.173)
0.227 (0.382)
BS(Age)2
−0.226 (0.538)
−0.584 (0.628)
0.708 *(0.331)
BS(Age)3
1.323 **(0.482)
1.708 **(0.590)
0.696 ***(0.203)
Sex = M (ref=F)
0.236 (0.185)
0.377 *(0.189)
−0.134 (0.167)
Age:Sex interaction terms
BS(Age)1:SexM
0.551 (0.475)
BS(Age)2:SexM
−0.402 (0.402)
BS(Age)3:SexM
0.703 **(0.243)
Year
−0.024 (0.014)
0.003 (0.017)
BS(Year)1
−1.349 (1.210)
BS(Year)2
−3.417 ***(0.612)
BS(Year)3
−3.215 ***(0.677)
Continent (ref. North America)
Europe
0.142 (0.173)
−0.140 (0.196)
−0.115 (0.069)
Other
−0.238 (0.328)
0.395 (0.296)
Constant
56.062 *(27.523)
−1.086 (33.910)
5.495 ***(0.684)
Observations
Runners
207
159
247
212
805
582
Notes: * p < 0.05; ** p < 0.01; *** p < 0.001.
For time-limited races (Figure 4), a time eﬀect was not signiﬁcant in 6- and 12-h events but it was
signiﬁcant in 24-h races, where running speed decreased over time. In all time-limited races, running
speed increased across age groups (Figure 5) and this trend was diﬀerent between boys and girls.
Figure 4. Running speed across years for time-limited ultra-endurance events for 6, 12 and 24 h. Fitted
values=line, points=observed mean values.
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Figure 5. Running speed across age groups for time-limited ultra-endurance events for 6, 12 and 24 h.
Fitted values=line, points=observed mean values.
4. Discussion
This is the ﬁrst study that examined the participation and performances in time-limited
ultra-endurance events and multi-day events in youth runners.
The aim of the present study
was to investigate the age-related participation and performance trends of children and adolescent
ultra-endurance runners, younger than 19 years of age, in time-limited events. Our hypothesis was
that participation numbers would increase over calendar years and time, more boys than girls would
participate in these events, and that performance times from boys would be faster. The main ﬁndings
were (i) an increase in the number of ultra-endurance participation over time and across races and
sexes, (ii) performance diﬀerences between boys and girls, with boys being signiﬁcantly faster than
girls only in the 12-h race, (iii) diﬀerences between running speed across age groups and continents
and (iv) variations in running speed over the years and diﬀerent age–sex trend in 24-h events.
4.1. Participation Trends
An exponential increase in participation numbers among youth ultra-runners was observed in
the last 30 years. The most popular time-limited race competitions were 24, 12 and 6 h long; however,
participation numbers were considerably smaller. The majority of ﬁnishers belonged to the older
age groups (16–18 years of age) and were mostly male. Our ﬁndings conﬁrm previously observed
participation trends [16]. In time-limited races, most of the ﬁnishers in the 6- and 24-h races came
from Europe but, for 12-h races, most originated from North America. A study investigating the sex
diﬀerence in 24-h adult ultramarathoners showed that most of the starters originated from Europe,
mainly France and Germany [6]. Only a small minority participated in multi-day events.
4.2. Diﬀerences in Age Regarding Duration of Races
The percentage of runners aged 10-13 years was rather high in time-limited races. The existing
literature for adult ultramarathoners investigated the age trends only for distance-limited races [2,21]
but it made no comparison between the diﬀerent kinds of ultra-endurance events. In the 6-h races,
the majority of the ﬁnishers were 18 years-old, whereas in the 12-h races, the majority of the competitors
were between 16–17 years of age. For adult ultramarathoners, it has been reported that the age of peak
running performance increased with race duration with time-limited events ranging from 6 h to 10
days [4]. Obviously, there is a diﬀerence between youth and adult ultra-endurance runners, where
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youth athletes seem to be older in longer time-limited races, in contrast to adult runners, where the
opposite was found.
4.3. Analysis among Diﬀerent Races and Sexes
Boys were faster than girls in the 12-h races, but not in the 6- and 24-h races. This is hardly
surprising, taking the physiological diﬀerences during and after maturation into account. For adult
ultramarathoners, men were generally faster than women in time-limited ultramarathons (e.g.,
24-h races) [6]. Women, however, have closed the gap with men in the last decade [6,17,22,23].
The mean ultra-endurance running speed was generally faster in boys than girls across all time limited
ultra-endurance races; however, this was only signiﬁcant for the 12-h races. Younger girls, under the
age of 15 years, were faster than boys in the 6-h races. One possible explanation for the latter ﬁnding
may be that girls mature physiologically earlier than boys and this may have given them an advantage
at this race distance. Another explanation may be that there were far fewer girls participating at this
particular race distance and that they may have been better prepared for this event.
4.4. Analysis in Running Speed Across Age Groups
In all time-limited races, running speed increased across age groups and was diﬀerent between
boys and girls in 24-h races, with boys being faster than girls. In other terms, boys and girls improved
their running performance with increasing age in time-limited races. However, they were still far
away from the age of peak ultramarathon performance which is generally achieved at ages beyond
35 years [2,4,21] and increases with increasing race duration in time-limited races [4]. It is well-known
that the age of peak performance in endurance sports increases with increasing length or duration of
the endurance performance [24].
4.5. Analysis in Running Speed over Years
The last important ﬁnding was that the running speed showed diﬀerences in the trend across
calendar years for the diﬀerent ultra-endurance events. A time eﬀect was not signiﬁcant in 6- and
12-h events but it was signiﬁcant in 24-h races, where running speed decreased over time. Taken
together, these youth ultra-runners were not able to improve their running performance in recent years,
although in some races in earlier years their running speed was higher than in recent years. Obviously,
there is a general trend in long-distance races that running speed decreased in recent years, and this
may be related to the general increase in participation numbers, but not necessarily an increase in
faster or more elite runners, that would increase the overall performance times.
4.6. Limitations
The analyzed data originate from one database (DUV-www.ultra-marathon.org/). We recognize
that there are several other national databases; however, the DUV is the largest ultra-running database
worldwide and has been used widely to address similar research questions in the adult population.
Inaccuracies in reporting or missing datasets are possible in such a large database. For the analysis of
particular national races, data from the race websites could be analyzed for future studies. Several
races have been grouped together, without taking into account the speciﬁc ambient, environmental or
terrain particularities, which can have an impact on the average performance time. To address this,
we recommend analyzing speciﬁc races in future.
4.7. Practical Applications
In last decade, a large increase in the number of ﬁnishers and annual races of ultra-marathons has
been observed. Following this trend, the number of children and adolescents competing in these races
has increased, too. Consequently, strength and conditioning trainers could face new challenges when
working with children and adolescent ultramarathoners, since the existing knowledge is based mostly
Int. J. Environ. Res. Public Health 2020, 17, 1628
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in studies on adult athletes. The present study added valuable practical information in the existing
literature with regards to trends in the participation and performance of children and adolescent
ultramarathoners. For instance, these trends varied by country; thus, the ﬁndings would especially
be of practical interest for strength and conditioning trainers working in countries with increased
participation of these age groups in ultramarathons. Future studies may investigate the same trends in
distance-limited ultra-marathons such as 100 km and 100 miles.
5. Conclusions
Comparing time-limited races from 6 h to 8 days, it was concluded that ultramarathoners younger
than 19 years of age participated mostly in 6-, 12- and 24-h races, and the majority of these athletes
originated from Europe and North America. Only a minority participated in multi-day events. Overall,
speed was faster in the older rather than in the younger athletes. Finally, the overall speed mostly
decreased across calendar years as participation numbers grew.
Author Contributions: Conceptualization, V.S. and B.K.; methodology, S.D.G.; software, S.D.G.; formal analysis,
S.D.G.; resources, E.V.; data curation, E.V.; writing—original draft preparation, V.S., S.D.G., E.V., T.R., P.T.N. and
B.K.; writing—review and editing, V.S., S.D.G., E.V., T.R., P.T.N. and B.K. All authors have read and agreed to the
published version of the manuscript.
Funding: This research received no external funding.
Conﬂicts of Interest: The authors declare no conﬂict of interest.
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Participation and Performance Analysis in Children and Adolescents Competing in Time-Limited Ultra-Endurance Running Events.
Scheer, Volker,Di Gangi, Stefania,Villiger, Elias,Rosemann, Thomas,Nikolaidis, Pantelis T,Knechtle, Beat