The Science Behind the Olympic Lifts
Updated: Aug 11, 2021
Before learning the Olympic lifts, it is important to first understand the principles and mechanics of the snatch and the clean and jerk to have a deeper understanding of the technique. In their very essence, these lifts involve accelerating the barbell upward, and as the bar stops accelerating upwards, the athlete uses force against the barbell’s inertia to accelerate himself or herself downwards into a low position to receive the bar. Even though these lifts are often split into three different phases – the first pull, second pull, and third pull - they are performed fluidly and at explosive speeds. During the first pull, the barbell is lifted off from the floor and stops until approximately mid-to upper-thigh level- which is the point at which the final upward explosion starts. The second pull is the part where the barbell reaches its maximum upward lift as the athlete reaches the fully extended position. Finally, during the third pull, the athlete transitions from an extended position into the receiving position under the bar.
These phases are based on Newton’s three laws of motion.
Law 1: A body at rest will remain at rest, and a body in motion will remain in motion moving uniformly straight unless an external force acts on it. Therefore, a barbell will remain on the platform unless the athlete applies force to it that is greater than the force of gravity acting on the barbell. Similarly, when a force is applied, a moving barbell will continue traveling upwards as long as the applied force and the momentum gained will be greater than the force of gravity acting on the barbell in the opposite direction.
Law 2: The force acting on the body is equal to the mass of the object multiplied by its acceleration (Force = mass x acceleration or F= MA). This means that the rate of change of momentum (the amount of motion occurring in something that is moving, calculated by using the formula: momentum = mass x velocity) is proportional to the force acting on the body and is in the same direction. In simple terms, applying more force will create a greater acceleration, and the greater an object’s mass, the less will the acceleration be given the same force is applied.
Law 3: For every action, there is an equal and opposite reaction. When the lifter pushes with the feet against the ground, the ground delivers a force of the same magnitude in return. Due to the earth’s massive size, the push of the athlete does not move the earth. However, the reaction force delivered by the earth on the body will be of massive help to the athlete in lifting the bar off the floor.
During the first phase of the snatch and clean, the athlete uses the strength of the legs and feet to push against the ground to create this reaction force that will help lift the bar upward. As soon as the bar lifts off the floor, the bar will keep accelerating upwards, helped by the athlete who keeps pushing off the floor until the athlete reaches the peak body extension and thus can no longer push against the floor. At this point, the bar has gained enough upward momentum to momentarily keep traveling upwards, even without additional force applied by the athlete on the bar. However, even though the athlete cannot push against the floor anymore, the athlete will keep pulling the bar with the arms. This pull with the arms will generate an opposite downward reaction of the same force on the athlete, which will help the athlete travel downwards as the bar is going upwards. The jerk, in contrast with the clean and snatch, requires the athlete to push the bar upwards instead of pulling.
The heavier the barbell is relative to the athlete, the less the bar will travel upward and the more the bar will travel downwards. In addition, the forces of gravity will help the athlete move downwards but also limit the upward trajectory of the barbell. At the end of this phase, the athlete will finish under the bar into the receiving position. In contrast with a heavy barbell, a lighter barbell will accelerate faster and travel higher. Therefore, the athlete will have less need to travel downwards into a full squat. The athlete can of course choose to reduce the force applied to a light barbell to receive it in a full squat.
These principles highlight the important things to consider when learning the Olympic lifts. During the first and second pull, the athlete keeps pushing against the floor to accelerate the bar upwards until the body is fully extended and cannot push anymore. At this, the athlete continues the pull to the bar with his arm as this action will help transition the lifter downwards to receive the bar. Even though these phrases are explored separately, the lift is performed smoothly and explosively in a single action.
Thanks for reading, and as always stay fit!
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