The left side is one of the most overlooked aspects of the hammer throw. With the emphasis of strength in our system, there has been a single minded focus on the right side in American hammer throwing. While the right side provides acceleration for the system, the left side must be active to reduce time in single support and allow the athlete to catch the ball sooner. Just like walking, to be a successful hammer thrower, the athlete must find balance between both the left and right sides.
The successful hammer throw must start with proper winds. The winds, are another article unto themselves. After the completion of the final wind, the right-handed hammer thrower settles into his entry position and pushes the ball from 270 through 0 and continues to strive to push to 90 degrees. However, between 0 and 30 degrees, the left side takes over. The left arm stays relaxed and allows the ball to run long around the shoulder axis, while the left knee begins to drive down at 90 degrees to minimize the time in single support and facilitate an early catch of the hammer between 180 and 230 degrees. It is difficult or impossible (depending on whose research you read) to accelerate an implement with only one foot on the ground, so it is important to reduce the negative acceleration that occurs in single support, which in turn allows for a longer double support phase to continue to accelerate the system.
It is important to “let the ball be free” on the left side, with a relaxed upper body, allowing the ball to continue in its natural path, instead of trying to muscle it and pull it out of its orbit. As the weight transfers back and forth from the right to left leg, It is important to balance the force of the right leg with an equal force of the left leg. This is seen by the athlete “digging in” at 90 degrees, staying on the sole of the left foot and attempting to curl the toes down while driving the knee down. The rotation of the system and the drive of the right foot will turn the athlete to 180 degrees where the “digging in” of the left foot caused the athlete to step forward producing the linear acceleration to the turn.
Too often hammer throwers “float” over the left side. This is seen when the athlete rises on the left knee, get onto the side of the left foot, and hangs in single support too long, resulting in over-rotation of the turn.