If it's just for fitness, I can basically treat you as a joke. If you have a real sword, don't say that 8kg is a 3 kg long sword. Even if you have two years of fitness experience, you can't get used to it, but the actual weapon is the show spring knife of Royal Guards, 1 kg 7 Liang. The cavalry knife of modern American army is only 2 Jin 2 Liang, which is already a wrist-destroying artifact. In the middle ages, European barbarians only had 5 kilograms of swords with both hands.

An 8 kg sword has a cross-sectional area of at least 70 square centimeters, about 2 centimeters thick and 35 centimeters wide. If you are willing to take it to the streets, I really have nothing to say.