Schwab, Sebastian
Rein, Robert
Memmert, Daniel
Article History
Received: 20 August 2018
Accepted: 19 November 2018
First Online: 4 December 2018
Compliance with ethical guidelines
:
: S. Schwab, R. Rein and D. Memmert declare that they have no competing interests.
: In all, 20 adolescent developmental soccer players (U15 and U17) with soccer experience between 7 and 12 years (<i>M</i> = 9.67, <i>SD</i> = 1.57), as well as 36 adult male soccer players from four local soccer clubs with soccer experience from 13 to 27 years (<i>M</i> = 17.56, <i>SD</i> = 2.93) participated voluntarily in this experiment. Participants were randomly allocated either to the internal group (<i>N</i> = 28) or external focus group (<i>N</i> = 28). Before commencing the experiment, an informed consent from one parent or from the adult himself was obtained from every participant in accordance with the Helsinki Declaration of 1975.