Kammala wannan jumla: Van Rooijen ya tafi Amurka a watan Janairun 2001 don yin karatu a Jami'ar Miami. Ta ci gaba da zama a cikin tawagar 'yan wasa a lokacin gasar tseren ruwa ta duniya ta 2001 a Fukuoka, Japan wanda ya zama abin takaici. A cikin duka relays, 4 × 100 m da 4 × 200 m freestyle, ita da ƙungiyarta an cire su a cikin zafin jiki. Ta kai wasan karshe na farko a shekara ta 2002 a Berlin a gasar
2002 Gasar Wasannin Ruwa ta Turai ta kammala a 8th a cikin 200 m freestyle. Akwai kuma lambar tagulla a gare ta a cikin tseren tseren mita 4 × 100 tare da Marleen Veldhuis, Chantal Groot da Wilma van Hofwegen da kuma matsayi na 5 a tseren mita 4 × 200. A Gasar Cin Kofin Ruwa ta Duniya ta 2003 a Barcelona ta rasa lambar yabo ta duniya ta hanyar kammala na 4 a tseren 4 × 100 m. Ta kuma sami matsayi na 7 a cikin 4 × 200 freestyle. Bayan shekaru uku ta koma gida kuma ta sami wuri a Dordrecht, tare da Topzwemmen West-Nederland a ƙarƙashin jagorancin mai horar da mai horarwa Dick Bergsma amma ta kasa samun cancantar shiga gasar Olympics ta 2004 saboda raunin da ya faru a kafada.