There is no fixed weight difference. A training arming sword may weigh within the same range as a tournament sword. For example, the MedievalExtreme training arming sword weighs approximately 1.5 kg, while Type 1 tournament swords range from 1.1 to 1.7 kg.
The main differences involve blade thickness, steel treatment, finish, balance, and durability. Training swords often use thicker construction and a rougher finish to withstand frequent pell work at a lower cost.