ab workout

[bob]

I really need an ab workout. Im 210 pds, 5'11'', and 19% . Everyday I walk 3 miles in the morning. I lift 3-4 times a week. Also what is H.I.T.T. Also i heard that if u sprint 30 seconds, and jog 30 up to 4 minutes will have a high metalbolism for 1-2 days. I cut out fast food, suger, salt, soda, bread, and late night snacking out of diet. i eat a lot of fruits and vegtables. the last month i lost 5 pds but i cant seem to lose anything else. PLEASE HELP!!!!!!!