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The split jerk is actually a two step with the back foot landing first and thus gaining traction first. This has the effect of pushing the bar forward under the bar as it locks out overhead.
This exercises teaches the proper “prancing” action of the front foot, while reinforcing the drive from the shoulders in front of the neck. If this is a problem of yours or one of your athletes, include the movement early in the session until the foot work becomes well ingrained. As more proficiency is achieved, the exercise can be gradually moved further back in the workout until it can be eliminated altogether.