Author’s address Dr Elżbieta Biernat, Physical Education and Sport Centre, Warsaw School of Economics, al. Niepodległości 162, 02-554 Warsaw, Poland elzbieta.biernat@sgh.
Author’s addressDr Elżbieta Biernat, Physical Education and Sport Centre, Warsaw School of Economics, al. Niepodległości162, 02-554 Warsaw, Poland elzbieta.biernat@sgh.