 The other two major international competition for track and field are organised by the IAAF . The IAAF had selected the Olympic competition as its world championship event in 1913 , but a separate world championships for athletics alone was first held in 1983 – the IAAF World Championships in Athletics . The championships comprised track and field competitions plus the marathon and <unk> competitions . Initially , this worked on a <unk> basis but , after 1991 , it changed to a biennial format . In terms of indoor track and field , the IAAF World Indoor Championships in Athletics has been held every two years since 1985 and this is the only world championships that consists of solely track and field events . 
