Delhi boy Tejaswin Shankar today smashed the 12-year-old national senior record in high jump with an effort of 2.26 meter while winning the gold on the opening day of the 32nd National Junior Athletics Championships in Coimbatore today.The 17-year-old Tejaswin achieved the rare feat of a junior athlete breaking the national senior record. The earlier national senior record was in the name of Hari Shankar Roy of West Bengal who had jumped 2.25 meter while winning a silver in the Asian All-Star Athletics meet in Singapore in 2004.