EVF is an acronym for Early Vertical Forearm. It is a technique the enables the swimmer to get the most out of their catch phase of the stroke and get the most power and propulsion from each arm pull. As the name suggests, it involves the hand entering the water and keeping the elbow high in the water such that the hand moves directly below the elbow with the forearm vertical in the water with the elbow above the hand. The utilizes the entire forearm in the pull rather than the opposite where the elbow bends down and the arm is in a horizontal and highly inefficient pulling position. The EVF technique is critial in getting the most efficiency out of your freestyle.