The barbell is a unique and essential tool for training in the context of maximum functional resistance against gravity. There is no other tool that can substitute. The barbell loads the body unilaterally, allowing the athlete to use both sides of the body equally to generate maximum force. There are a handful of exercises which the barbell is best known for, together comprising basically the sports of Powerlifting and Olympic Weightlifting.
The “Big Lifts” are rightly regarded as fundamental to strength and fitness. From Powerlifting we get the deadlift, squat, and press; and from Olympic Weightlifting we get the clean & jerk and the snatch. The powerlifts develop slow strength and proper lifting posture, and may be regarded as foundational to the Olympic lifts, which develop explosive power.