Hard pulling with straight legs is a heavy training action. Generally, it is best to use barbells for weight training, which will be safer and more stable, and it is easier to lift more weight. Barbells and dumbbells belong to free-weight equipment, but they also have their own characteristics. Barbell is characterized by stability, which is more stable, safer and easier to complete than dumbbells with the same weight. Dumbbells are characterized by flexibility, freedom of force and large range of movements. Under the same weight, dumbbell moves more than barbell, which stimulates muscles more and is more difficult to complete. Therefore, in training, barbells are usually made first, and then dumbbells are made.