Your left knee can tall you a great deal about the power of your swing.
Here's a good golf tip; next time you play watch the left knee of the other golfers in your group.
At the top of their back swing some golfers left knees will point straight out in front of them. Their hips have not turned. Their balance is poor and their possibilities for making a powerful swing are limited.
This group of golfers will tend to use their shoulders and hands more than most when they swing the club. They will tend to either slice the ball or pull it to the left.
Good golfers on the other hand have their left knee turned in towards their right at the top of their back swing and their weight is on their right foot.
This group of golfers have turned their hips and coiled their bodies on their back swing and they are in good position to drive into their left side when they swing the club. Because their hips turned on their back swing they can initiate their down swing by rotating their hips. This produces a powerful, well-balanced swing with a good likelihood of a long straight shot.
All the best
The Golf Bandit