The basic knowledge about golf swing learned from the last several months is becoming more and more obvious in practice. The basic rules of a good swing may include balanced and stable stance, straight back, eyes on the ball, and no head-turning and sufficient follow-through.
One critical part I learned new in the past week is club head turning. Jie checked out an instruction video from the city library about golf. This instruction video stressed that there was no perfect swing. Golfers have put too much emphasis on the golf swings. In stead, the golfers should pay more attentions to basic instincts without thinking too much about swings. I felt that the teaching was interesting. But it did help me understand the physics of the golf swing.
Actually there are two swings at the same time. One swing is the shaft swing. The shaft is an extension of our arm length. Another swing is the club face swing, which is an extension of our palms. The shaft swing before hitting the golf ball is about 180 degrees. The club face (for the iron) can add additional 180 degrees of turning. I tried to incorporate this understanding into my practice. It seemed the driving distance could be increased. At least I could feel the additional power of the impact when hitting the ball if the turning of club face was done correctly.
I did try a simple calculation to see if the secondary club-face turning could add additional distance to the strike. If we assume the speed of the shaft (plus the arm length) is ω with L as the length while the club-face turning speed is ω with the small length l. The total speed is then V = ω (L + l). Suppose l/L = 6%. Then the swing speed can be increased by 5%. However, the fly distance of golf ball is proportional to V to the 3/2 power. Then the distance can be increased by 9%. For a 5-Iron, the normal driving distance is 170 yards. A 9% increase in distance would make that to 185 yard. That is 15 yards additional distance without forcing a more powerful swing.
Another feel I had learned in the last week was that the stance had to be stable until the down-swing had begun. During the entire back-swing (preparing for the down-swing) I have to keep my stance stable without moving my lower body sideways or up/down. From the beginning of the down-swing, my body turns together with my arms. That is the time when I can release my stable stance with the turning move of my right leg. So the right leg is pulled away by the moving arms and body. That is the time I can feel the powerful swing. This might be what they call tempo. I could not say I have fully mastered this tempo, but I can say that I start to get the feel of it.
