As you begin the forward swing with your hitting arm on a one-handed backhand, the other arm needs to extend back and away from your body.  This movement serves as a counter-balance, and keeps the back shoulder from rotating forward during the swing.  While the two-handed backhand is more rotational- like on the forehand, your hips and trunk rotate through the shot- the one-handed backhand is a more lineal stroke.  Extending the non-dominant hand out and away from the body “anchors” this lineal movement on the one-handed backhand.

There are differences in what the non-dominant hand does on the finish of the swing depending on the shot you choose.  For a slice backhand, the hitting arm finishes low and in front of the body so the non-dominant hand extends away and upward.  On a topspin drive, the hitting arm finishes above your head so the non-dominant hand is conversely extended down and away from your body.  This counter-balance action is crucial, particularly when the shot is hit on the move.

Article by Bill Mountford, Director of tennis at USTA National Tennis Center