János Gróz was one of the founding fathers and was considered the dominant personality in Hungarian beach handball.
In 2013, he also took over the Hungary women's national beach handball team from József Farkas, where he was previously assistant coach from 2009 to 2012.
[2] With the team he won the titles at the European Beach Handball Championships in 2013 and 2015.
Within nine years he won with the team, including Bozsana Fekete, his daughter Kitti Gróz,[4] Ágnes Győri, Fruzsina Kretz, Mariann Rovnyai, Emese Tóth, Nóra Leila Bozsó, Renáta Csiki, Fanni Friebesz, Viktória Vígh, Adrienn Zsigmond, Ágnes Kókai, Rebeka Benzsay, Csenge Braun, Sára Léránt and Ramóna Vártok.
In 2015, 2016 and 2018 he won the European Beach Handball Tour with Szentendrei NKE, in 2015 and 2018 the Champions Cup.