Career
Callender represented Trinidad and Tobago at the 2008 Summer Olympics in Beijing. He competed at the 4 × 100 m relay, together with Marc Burns, Aaron Armstrong, Keston Bledman and Richard Thompson. In their qualification heat (without Callender) they placed first in front of Japan, the Netherlands and Brazil.
Their time of 38.26 was the fastest of all sixteen teams participating in the first round and they qualified for the final.
Armstrong was replaced by Callender for the final race and they sprinted to a time of 38.06 seconds, the second fastest time after the Jamaican team, winning the silver medal. Callender set new personal bests in the 100 and 200 meters at the Grande Prêmio Brasil Caixa meet in May 2009, recording times of 10.16 and 20.40 seconds respectively.
Since then, he has improved his 100 m personal best, to 10.05 son 100 m: 10.05 s (wind: +04 m/s) – Zürich, 28 August 2009 200 m: 20.40 s (wind: +03 m/s) – Belém, 24 May 2009 400 m: 48.47 s – Kingston, 26 January 2008.