The current world indoor rowing champion of the lightweight 30-to 39-year-old male division is training hard at UC Davis to defend his title for 1996. Mike Slavin, a UC Davis biomedical engineering graduate student, will try to qualify Feb. 11 in the 10th annual Golden State Indoor Rowing Championships in Sacramento. The Sprints World Indoor Rowing Championship will be held in Cambridge, Mass. two weeks later. Slavin has modified his training this year, adding a leg press session to his workout schedule to "wake up" his fast twitch muscle fibers because the event just became more difficult for him, he says. The race distance was shortened by 500 meters, favoring more physical power and less physical endurance, which Slavin says is not his forte. Slavin works out on the Rec Hall rowing machines two to three times a week to prepare for competition.