The Footbonaut as an Innovative Diagnostic System

Differentiating Response Times in Soccer Players of Different Age-groups

Christian Saal

, Sven M¨uller

, Harald Fiedler

, Jan Mayer

and Ralf Lanwehr

Fakult¨at Sport, Hochschule f¨ur Gesundheit und Sport, Technik und Kunst, Berlin, Germany

TSG 1899 Hoffenheim, Hoffenheim, Germany

Business and Information Technology School, Iserlohn, Germany

1 OBJECTIVES

The Footbonaut is a high-tech measuring instrument

for the training and diagnostics of agility in soccer

(Saal et al., 2013). It can be used to measure the

response time and precision (goal/no goal) regarding

a highly soccer speciﬁc reaction task in order to es-

timate agility performance. Agility is deﬁned as ”a

rapid whole-body movement with change of velocity

or direction in response to a stimulus” (Sheppard and

Young, 2006). There are indications that suggest that

agility helps to predict talent (Reilly et al., 2000). To

our knowledge there exist no scientiﬁc studies target-

ing the application of this measuring instrument in di-

agnostics and training. The aim of the cross-sectional

cohort study to be presented here, was to test if the re-

sponse time results from tests in the Footbonaut were

an appropriatetrait to distinguish between age groups.

We assume that professional soccer players have a

shorter response time measured by the Footbonaut.

2 METHODS

Data on soccer players (n = 101, male, U14 to pro-

fessionals) representing TSG 1899 Hoffenheim dur-

ing the 2013-2014 season were collected. The sam-

ple was divided to seven standardized age groups.

The Footbonaut (CGoal GmbH) was used to measure

the response time of soccer speciﬁc reaction tasks.

The Footbonaut consists of a playzone (artiﬁcial turf,

14x14 m) and is surrounded by four walls. The walls

include 72 high and low positioned square panels,

each equipped with light barriers and light-emitting

diodes (LED). Eight ball-throwing machines are in-

stalled behind the middle panels in each wall (ﬁg.1).

The other 64 panels are used as targets. Stimuli,

ﬁrst at the ball-throwing machine then at the target

panel, were given by the LED and an accoustic sig-

nal. Light barriers were used for time measurement.

Table 1: Settings deﬁned for each Session in the Footbo-

naut.

Parameter Value Description

Canon Power 50 % The speed of the ball. 50 %

≈ 50 km/h

Trials 32 Number of Balls per Session

Random 360

◦

Targets in a range of 360

◦

Vertical angle 2 Angle of inclination of the

ball-throwing machine

Shot delay 800ms Time difference between the

stimuli

Note. Only low targets and ball-throwing machines were

used.

Testing procedures included the setting from Table 1.

We used uniquely randomized combinations of ball-

throwing machines and target panels. Which means

that the sequence was identic for each subject.

Each subject received the same instruction ”play

as fast and accurate as possible”. There was a short

practice session before the measurement. The sub-

jects started the session in the middle of the test zone.

After stimuli identiﬁcation the player had to control

and pass the ball into the right target panel. The ath-

letes performed two sessions with 32 trials in a con-

secutive order. Means for the response time of the 32

trials in each session were calculated. The best mean

was used for statistical analysis. The seven groups

were compared using a Kruskal-Wallis rank sum test.

For pairwise comparison we used a Wilcoxon rank

sum test with a false discovery rate adjustment.

3 RESULTS

Means of the best series show that professionals

have a shorter response time than others (tab.2). A

Kruskal-Wallis test was conducted to evaluate dif-

ferences among the seven age groups (U14 to pro-

fessionals) using means of response time that re-

sulted from a soccer speciﬁc task in the Footbo-

Saal C., Müller S., Fiedler H., Mayer J. and Lanwehr R..

The Footbonaut as an Innovative Diagnostic System - Differentiating Response Times in Soccer Players of Different Age-groups.

 2014 SCITEPRESS (Science and Technology Publications, Lda.)

Figure 1: Footbonaut with testzone, ball throwing machines (A), target panels (B) and detailed view of ball throwing machines

and light barriers.

Table 2: Descriptiv statistics for the response time in the

Footbonaut of soccer players different age groups.

group n M (SD) 95% CI

U14 12 2.47 (0.39) [2.22, 2.72]

U15 16 2.32 (0.17) [2.23, 2.41]

U16 13 2.45 (0.28) [2.28, 2.62]

U17 13 2.52 (0.20) [2.40, 2.64]

U19 9 2.20 (0.20) [2.05, 2.36]

U23 17 2.18 (0.30) [2.02, 2.34]

Proﬁs 21 2.09 (0.14) [2.02, 2.16]

Note. CI = conﬁdence interval

naut. We found signiﬁcant differences in the best

response times between the seven groups (χ

(6, N =

101), = 35.82, p < .05). Follow-up tests were con-

ducted to evaluate pairwise differences among the

seven groups, while controling the false discoveryrate

(Benjamini and Yekutieli, 2000). The Results of these

tests indicated signiﬁcant differences (tab.3) between

the professionals and age groups lower than U17. No

pattern was found for precision outcome.

Table 3: Pairwise comparisions of differences in response

time in the Footbonaut between the age groups using

Wilcoxon rank sum test. Table shows p-values.

U14 U15 U16 U17 U19 U23

U14

U15 .26

U16 .78 .35

U17 .81 .03

∗

.64

U19 .12 .18 .10 .01

∗

U23 .05 .05 .02

∗

.00

∗

.70

Proﬁs .00

∗

.00

∗

.00

∗

.00

∗

.23 .50

Note.

∗

p < 0.05, adjustment = false discovery rate

4 DISCUSSION

The aim of the study presented here was to test if the

response time measured in the Footbonaut is an ap-

propriate trait to distinguish between age. The results

show signiﬁcant differences between the profession-

als and age groups lower than U17. We explain the

result with the highly speciﬁc movement pattern and

change of direction requests that the Footbonaut al-

lows. Further research assessing the validity and re-

liability of the Footbonaut test procedures are neces-

sary, especially regarding the measurement of player

performance changes over time.

REFERENCES

Benjamini, Y. and Yekutieli, D. (2000). The control of the

false discovery rate in multiple testing under depen-

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Reilly, T., Williams, A., Nevill, A., and Franks, A. (2000).

A multidisciplinary approach to talent identiﬁction in

soccer. Journal of sport sciences, 18(9):695–702.

Saal, C., Zinner, J., B¨usch, D., Werner, C., and

Uckert, S.

(2013). Der Footbonaut als Mess- und Information-

ssystem im Sportspiel Fußball. Zeitschrift f¨ur Gesund-

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Sheppard, J. M. and Young, W. B. (2006). Agility literature

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