The proper amount of grip pressure can make or break your golf swing. It can also help you from slicing or hooking the ball. The only contact you have with the golf club is through your hands. Having the correct golf grip is one thing but you must also have the correct amount of grip pressure.
What do I mean by grip pressure? It's how tight you're gripping the golf club. By watching the videos above you'll get a better understanding about what I'm talking about. Just click on the three lines in the top left corner of the YouTube window and pick a lesson.
Next time you're on the practice range try hitting some golf balls with a somewhat loose light golf grip. Then try a very tight grip. You will find that the tighter you grip the golf club the more restrictive your golf swing becomes.
A tight grip promotes a tight restrictive swing with slow club head speeds and no power. On the other hand a loose grip promotes a loose free flowing swing which generates very fast club head speeds with lots of power.
Experiment with different grip pressures. I'm sure that you'll discover that a lighter grip is better than a tighter one. Give it try!
