Double Pendulum

The double pendulum model of the golf swing dominated swing analysis for decades. It was based on thinking about the golfer as a two-lever system. Shoulder to wrist was considered as a single lever connected to a second lever, wrist to clubhead. The wrist is the hinge in the two-lever model.

The classic 1968 book, "Search for the Perfect Swing" by Cochran and Stobbs still stands as the definitive description of the model. Careful reading of the book reveals a wealth of insight and ideas about the swing. But they were gradually overlooked as the two-lever model gained credence.

The model began as a useful first step in describing swing mechanics. Pictures of golfers could be analyzed, lines overlaid at strategic positions, angles measured, and calculations made with math that was not too difficult to follow. A popular science approach to human physiology was incorporated into the analyses. Books and journal articles were written. Classes taught to teaching professionals fell under the spell of the two-lever model. Student golfers were taught the rigid lead arm and getting into strictly correct positions. Two-lever dogma found it's way into teaching the swing.

It was soon forgotten that the double pendulum model started out as a simple way to think about how to describe clubhead speed, not how to swing the club. A model with more than two levers was acknowledged as better but it made the math too complicated. The sequence by which a golfer uses the muscles in the body to swing the club was understood to be important but not incorporated into the two-lever model. It was assumed that the key muscle sequences already had already occured before the two-lever action kicked into play.

Then, 3D motion capture technology entered the picture and the world of swing analysis was forever changed. It has redirected thinking about how to generate speed and power to a kinematic approach. The sequence and timing of how body segments move during the swing relative to each other could be measured, overcoming 2D video limitations. This kinematic sequence could be viewed as your swing signature, and understanding it has become the new platform upon which modern swing instruction is built. We have begun to identify the key concepts on our swing analysis website pages.

Angle of Descent

The vertical angle of descent is the angle at which the ball hits the turf relative to the ground. It's calculated by advanced radar launch monitors from ball spin and trajectory data. Angle of descent is an indication of the distance a ball will roll after it hits the ground. 

Angle of descent is an important consideration in fitting drivers for maximizing total distance. When the angle of descent is too high, roll of the ball after it hits the ground is minimal and total distance is reduced. When the angle of descent is too low, it indicates the launch angle at impact was too low to generate enough carry (not high enough) for maximum distance. 

Maximizing distance depends on optimizing launch angle and ball spin for increased carry distance, and optimizing angle of descent for increased roll distance. The optimum angle of descent typically falls within a 10-degree range, and the distance effect can be 10 - 15 yds or more for a driver depending on clubhead speed and other factors. The effect of roll on achieving extra distance after impact is most signifcant on firm fairways.

Several different parameters affect angle of descent and launch angle, and an accurate launch monitor is required for the measurements. Your eyes are not as accurate as a properly calibrated Doppler radar launch monitor that can measure ball flight directly for the best driver performance. 

Standing on the range and watching your ball flight is not a reliable way to judge distance. Looking at the shape of the ball trajectory is not a reliable to do it either. There is no way eyes alone will allow you to optimize club performance. If you are at an OEM demo day where a launch monitor is present, be sure it's turned on and making measurements of your swing in real time if you want to use distance to fit your clubs. 

Why Buy Same Clubs?

Why do golfers often buy the same clubs when they decide they want something new to help improve their game? It happens far more than you would expect.

It's partly because golfers get attached to a brand name. It becomes their favorite, and it's hard to turn away from a favorite brand. These golfers want to believe the new favorite-brand models will be right for them no matter what actual testing shows. Golfers will look for reviews and evaluations that do not conflict with brand loyalty. Golfers want better performance but they often buy familiarity because it's a comfortable choice.

Endorsements and the ads on TV and in magazines create a familiar environment when looking at the new models. Switching to different clubs other than another heaviliy marketed brand can be intimidating. We understand the problem. It's familiar territory for lots of golfers. 

We think clubfitting and golf instruction offer great opportunities to make major changes in the brand or style of club you are playing. The key is to get a thorough swing analysis to go along with the fitting to help you make a satisfatory change. If you want to improve your game, it may be time to make a clean break with the past and try something quite different when clubfitting shows an unfamiliar brand is the best choice. 

Measured or Fitted?

Were you measured or were you fitted? How do clubs get fitted to your swing. How much time does it take?

The experience of most professional clubfitters indicates about 2 - 3 hours may be needed to find the best fit of clubs to your swing. You should be testing shafts and clubheads from a varied selection that allows you to find a combination to match your swing mechanics and give the performance you seek.

The fitting system should be sufficiently large and diverse to assure that the best options for you are available. An interchangeable shaft and club head system gives you the widest range of combinations to test. For example, changing the shaft while keeping the same clubhead makes it easier to determine the best shaft for your swing.

Often a followup fitting session is recommended or needed to identify the best combination of components and properties for your swing. You may find it most effective to focus on irons in one session, drivers and fairway woods in another session, and the short game separately. Playing a test club between sessions can confirm the performance of what you tested and provide feedback to your clubfitter.

A launch monitor will be needed to collect the club performance data. Your eyes are not a good enough judge of distance and accuracy to determine what really happened. Video is a great help in evaluating your major swing traits -- you should know if the fade or slice in the ball flight comes from an over-the-top swing plane, a mismatch in club path and clubface angle, the wrong shaft, a clubhead weight and balance issue, or something else. A popular cliche applies here: if you don't measure it's just a guess.

The best clubfitting is based on professional swing analysis with 3D motion capture. If you want clubs fit to your swing, then the clubfitter needs to understand your swing mechanics. 

Clubfitting needs to be done live and in person. We have an impact tape figure or two in our website to illustrate the need for direct testing. Subtle changes in shaft stiffness or weight distribution can result in different ball impact patterns. Finding the right shaft and clubhead combination that yields an optimum clubface impact pattern requires direct testing. 

Our advice is to find a professional clubfitter with the necessary expertise and equipment for testing and analysis. And don't forget to enjoy the process. Clubfitting is part of the fun in getting new clubs.

Iron Loft Confusion

Loft angles of irons can be confusing when considering a new set. The confusion comes from the lack of fixed standards for the specifications of individual clubs or how those specifications may vary through the set. For example, a 6-iron can be manufactured with a loft of 32 degrees in one set of irons or a loft of 26 degrees in another set. The difference in lofts between irons within a set can range from 2 degrees at one end of the set to 6 degrees or more at the other end of the same set. These variations may be found in irons from different manufacturers or in different models of irons from the same manufacturer. Here is the main reason for this circumstance.

Loft angle is an easy specification to change when the marketing department tells the engineering department to increase the performance in a new model of irons. The company can reduce the loft by one or two degrees to increase the distance the new irons will yield at the same swing speed. It's difficult to resist this strategy when competitors do it, so just about all companies follow this practice. 

Consequently, when you compare the performance of clubs that you are considering, knowing the loft angle will help you make a meaningful choice. A quick look at the manufacturer's specifications will give you much of the information you need. It helps to know the new 6-iron you are testing has a loft angle more like your old 5-iron or 4-iron. Reducing the loft of a 6-iron by 4 degrees essentially puts a short 5-iron in your hands, and that's how you get more distance. 

It's also important to consider the effects of changing loft angles on your overall club set makeup. For example, is there a big loft angle difference between your short irons and wedges, and is there enough of a loft angle gap at the long end of your set? You may want to replace a seldom-used long iron with a much needed extra wedge. Custom club sets allow you to get exactly what you need and will likely save you some money.

An important part of clubfitting is to optimize the loft angles in your club set makeup. Consideration of your swing technique and range of motion will also help in assembling the best set for your game. We think clearing away the confusion in loft angles is a good place to start. Measuring the distance you achieve for each club with a normal full swing is a key part of clubfitting that helps you get the optimum loft angles for your set. Testing with a launch monitor that measures both ball speed and clubhead speed is required because the eyes might tell the brain what it wants to learn and not what actually happened. Eyes are funny that way.