Common barbells include Olympic barbells, small-hole barbells, W-shaped curved bars and mesh barbells. Olympic barbells, referred to as Olympic bars, have international standards in length and weight. It is a barbell for Olympic weightlifting. It is 2.2M long and weighs 20KG. The diameter of the holding part is 28MM, and the diameter of the hanging bell plate is 50 mm Olympic poles are generally used in gymnasiums to do heavy movements such as squat, bench press and prone rowing. The weight of the small-hole barbell is much lighter than that of the bar, and the length varies from1.2-1.8m. The diameter of the hand-held part and the hanging weight plate is generally 28MM, which is suitable for arm training, barbell practice and home use. W-shaped bent bar and eye-shaped barbell are both special barbells for arm training, which can provide different training angles for forearm when bending and arm flexion and extension, thus achieving different training effects.