Trajtenberg took up taekwondo in 1968. His Teacher was Nam Sung Choi, one of the taekwondo pioneers in Argentina, who had arrived one year earlier in 1967. Trajtenberg obtained his black belt degree in 1971. In 1977 Trajtenberg gave up his university studies for good, only one year short from graduating as an electronic engineer, with the goal of devoting himself full-time to the teaching of taekwondo. In 1980 he opened the “Centro Argentino de Taekwon-Do” with Héctor Marano.