An impact bag is a great swing aid to help you work on creating the ideal position to be in as you strike, or impact, with the golf ball.
The ideal position to be in at impact, as a right handed golfer, is to have your weight more on your left foot, about 75% on your left foot.
Your hips should be rotated to the left and turned towards the target, with your right heel rising from the floor and your right foot beginning to rotate on to your right instep. Your left arm should be straight and extended down the front left side of your body so that your hands are in front of your left thigh. The club shaft should be leaning forwards, with the handle of the club more to the left than the club head. This is a great position to strike the ball from and one where you will generate a great deal of power and club head speed which in turn will produce golf shots with plenty of distance.
What an impact bag can help you with, when used correctly, is creating this impact position and this forward lean in the club shaft before you strike the golf ball.
You can use the impact bag in two ways. Initially, place it opposite your left foot. Practice swinging the golf club back away from the bag and then returning it so that you are rotated with your hips to the left of their original start position and your weight on your left foot as previously discussed. Work on striking the club head into the bag to create a straight line from your left shoulder down your left arm to your left hand and then into the club shaft and club head. This straight line will be created down your left side if the impact bag is placed opposite your left foot, which is correct.
Another way that you could use the impact bag to improve your impact position is to place it upright on it's side in the centre of your stance. Make a backswing away from the bag and work on rotating your hips to the left and towards the target as you swing down. To create the forward lean in the club shaft that gives you more powerful and consistent strikes, work on contacting the shaft into the upper right side of the impact bag so that the bag falls over to the left. This will ensure that your hands are leading the club head, they are more to the left than the club head is, through the impact position. If the club head strikes the bag before the shaft strikes, you are making more of a wristy, flicking action with the club and this will cause you to make an upward action towards the ball and produce shots where you hit the top of the ball, with very little power. Swing towards the bag with the hands leading and to achieve this make sure the shaft strikes the upper part of the impact bag before the club strikes the bag.
Working on these drills will help you to create a solid left side at impact and help you to hit your golf shots further, more consistently and with increased accuracy when out playing on the golf course.