@article{FuehnerKlieglArntzetal.2020,
  author    = {Thea Heidi F{\"u}hner and Reinhold Kliegl and Fabian Arntz and Susi Kriemler and Urs Granacher},
  title     = {An update on secular trends in physical fitness of children and adolescents from 1972 to 2015},
  journal   = {Sports medicine},
  series    = {a systematic review},
  volume    = {51},
  number    = {2},
  pages     = {303 -- 320},
  doi       = {10.1007/s40279-020-01373-x},
  year      = {2020},
}