A program that taught college women ways to prevent sexual assault cut in half the chances they would be raped over the next year, a Canadian study found. It was the first large, scientific test of resistance training, and the strong results should spur more universities to offer it, experts say. Five percent of freshman women who went through the four-session program said they had been raped during the following year, compared to 10 percent of others who were just given brochures on assault prevention.