Golf Club Flex

6th hour:

Brandon Starr, Kevin Welker, Manny Maniaci

Flex on a golf club shaft:
We will be measuring the flex on a golf club shaft and how much it flexes from the point of impact from the bottom of the club, to the ball. Also we will be measuring the angle of your swing, and seeing how it will effect the flex of the club when it comes into contact with the ball.

We will be using the high speed camera to view the angle of the swing and how it will affect the speed of the club. Also to see how much the club flexes when force is exerted on the ball.
Taylormade R7 Driver Stiff Flex
King Cobra High Speed regular Flex
Golf Balls
High Speed Camera
We decide that we would be measure the amount of flex a golf club shaft has when it comes into contact with the ball. However while experimenting we ran into a problem, we would be unable to measure the amount of flex from the point of contact. The high speed camera would not be able to measure it because the changes would be to minimal.
To compensate we would measure the amount of flex a club has during the upswing and downswing. We would be able to see the difference in each swing and record how acceleration, vlocity and momentum changes.
Why is golf club flex important?

"Flex" refers to the ability of a golf shaft to bend as forces are applied to it during the golf swing.

Those forces are generated by the type of swing that you have - fast or slow, smooth or jerky.

There are five generally used ratings for shaft flex: Extra Stiff, Stiff, Regular, Senior and Ladies, usually denoted by the letters X, S, R, A and L.

Shaft flex impacts, either directly or indirectly, the accuracy, trajectory and distance of your shot.

As the shaft flexes throughout the swing, the position of the clubhead changes. And the face of the club must be square (perfectly straight) at impact to get the most out of the shot. If you have the wrong flex for your swing, there is less chance that you'll make contact with the ball with a square clubface.

Importance of Golf Stance:
Some factors that are important in a golf stance are: bending at hips to address the golf ball, flex in the kness, ankle flexion, and spine extension. Each aspect can dramatcly affect your swing due to the changes in momentum and energy around your body.
Torque in a Golf Swing:
Torque = Moment of Inertia x Angular Acceleration

The majority of torque in a golf swing is generated by the glutes, hamstrings, quads, and core of the body. The torque created in the lower body creates acceleration in the upper body as energy is transferred into the clubhead. Studies indicate muscle activity also occurs within the pectoralis major (chest), upper back, and rotator cuff muscles during the swing. The downswing is complete at the point at which impact occurs with the golf ball.


During a golf swing there is a build up of torque with the rotation of the body, and weight transfer. There are two components to the weight transfer both during the backswing and downswing: a side to side weight transfer, and a dynamic weight transfer. Dynamic weight transfer refers to the sequenced synchronization of the angles of both the lower and upper body, while rotating the hips and shifting one's weight from side to side. In order to gain the maximum torque from ones body during the golf swing, this total weight transfer must be executed in a single fluid rotational movement.

This dynamic movement adds to the power and have accuracy of direction of the force imparted to the golf ball.

Manny's First Shot:
 On the first shot manny uses a driver. The acceleration of the club is slow to start at first, however a bit of flex occurs during the middle of the upswing. This is due to the momentum of the club and Manny's body which causes the club to flex.

As Manny continues to swing higher the clubs velocity increases and the club begins to flex at the peak of the upswing. This is possibly the largest amount of flex during the entire swing. Most of this flex is due to Manny changing his momentum from the right side of his body to the left.
 During the downswing the club accelerates very quickly to 87 m/s. Also the club begins to flex during the end of the down swing due to the change in momentum taking place in the swing.
At this moment while the club is flexing the momentum in the club is changin the opposite way which changes it to negative.
 velocity of club head=86.943 m/s
weight of shaft=70g
weight of club head=198g
total weight of club=268g
kinetic energy=10.12j

One thing that you learn from studying the physics of a golf swing is that if you start the movement early in the lower part of your body the kinetics involved will gradually be transferred along with the energy from your hips and shoulders so that you end up with a much more powerful swing that requires a lot less effort.

Another aspect that is important to using the physics of a golf swing to improve your game is to make sure that you are making full use of your club. Of course you can help this aspect of your game by buying the best clubs that you can afford. You will still need to be able to use them well to get the best from your game.

 We all learned a great deal from this physics of sports project. It was interesting to see all the changes from the high speed camera. Also we were able to see all the changes in body movement and how it can affect a golf swing. Each part of the body has different energy that transfers throughout the body. All of that energy is transfered throughout the swing.
Things we could have done to improve on our project are measuring the angle of each swing. That way we could have better measured the torque of the body during the golf swing. Also we would have been able to see the difference in anlge from each club.