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What Makes A Racquet Powerful?

The days of serve and volley tennis are long past, and the era of hard-hitting, topspin tennis is in full force. Along with this comes the slow death of what we would consider the classic control racquet. While there will always be control racquets around, there is a definite shift in the scale towards being more powerful than in days past.

Decades ago, when the Prince Graphite was released, it was one of the classic control racquets. It has a thin 19mm constant beam width, small 93sq. in. headsize, and buttery soft flex. Even a personal favorite, the Wilson Pro Staff 6.1 Classic has undergone so many changes that it bears little resemblance to the current Six-One variation. A stiffer and wider beam contributes to increased power in what is considered a very control oriented racquet today. It’s obvious to see that the power scale has not moved in a direction, it has completely shifted as the high control frames of the past are gone, replaced by more powerful alternatives.

So this begs the question, what exactly is it that makes a racquet powerful? Like so many other subjects in tennis, the answer lies in a number of different factors. A partial list includes head size, beam width, string pattern, weight, balance, as well as many others. With all of these factors, how do you know which ones to augment without creating too great of a drawback? Borrowing from the ancient philosophy of Alchemy in which equal exchanges are necessary, all aspects of a racquet undergo the process of gain and loss. In particular, as a racquet becomes more powerful, greater amounts of control are lost.

In the past, racquet purchases were made by finding the frame with the greatest amount of control that would still provide adequate forgiveness. This theory has given way to the method of using the frame with the absolute most power that you can comfortably control. This means very different things for each player as factors such as age, frequency of play, athletic ability, and more impact the decision. You would not recommend the same racquet for a state-ranked junior playing 30 hours a week as you would a 45-year-old man that plays two hours a week at his club, so why is it that such a large majority of players are using the exact same racquet?

The answer is in marketing, and the inability for some people to accept their own limitations and admit that sometimes it is better to use what is appropriate for their needs, instead of what they want to use. So with the thinking of finding an appropriate racquet and the goal to get the most powerful frame within reason for our needs, we set about looking at the various factors and their influence.

First we want to talk about static weight, because it has a surprising influence that may seem contradictory. Based purely on physics, a heavier frame will provide additional power. Under the assumption that the racquet is not so heavy that it limits the player’s physical capability in regards to the speed of the swing, a heavier frame provides greater momentum at impact and so provides more energy. So why is it that most frames that are labeled as control racquets are heavy in weight? That has to do with our next two factors, balance and swing weight, which are closely and confusingly tied to weight. If you would like a more thorough understanding of these three measurements, please see our explanation here.

If we try to imagine the near impossible situation in which we have two identical racquets that only vary in the location of the balance point, it makes logical sense that the one that balances closer to the tip of the head will provide greater power. When comparing a head light racquet against a head heavy frame, to understand it simply, think of the situation as a hammer. Which way provides greater force, holding the handle and striking with the heavy metal head, or holding the head and striking with the much lighter handle? This is just one way how a light racquet, but with a head heavy balance, can provide greater power than a frame with a heavy static weight but head light balance.

The weight and balance tie in with swing weight, which is another way of saying the dynamic weight of the racquet. While the static weight is purely a measure of the mass at rest, the dynamic weight is effectively a measure of how that weight behaves in motion. As such it depends not only on the weight itself, but on the distribution of that mass. Again assuming two racquets that are identical in every aspect other than the dynamic measure, the frame with the higher swing weight will provide greater power because it acts on the ball as if it were a heavier object. This is of course, also assuming that the increased swing weight does not result in a decrease in the speed of the frame.

Another simple to understand factor is that the length of the racquet will impact the power potential. This is based entirely on the physical concepts of leverage and circular motion. Obviously the racquet does not travel in a true circular motion, but it can be reasonably modeled that the racquet moves about a central axis. With this in mind, the speed of an object increases at you move further from the rotational axis, meaning that during swing, the tip of the racquet will be traveling faster than the grip. When you increase the length of the frame, you are extending the ideal hitting location further from the body. This means that assuming the player’s swing does not change, a longer frame will be moving faster at the ideal impact location. The increased speed means that there is a greater amount of energy being contributed from the racquet, leading to a greater power potential.

The next feature we look at is the head size, and it should be fairly obvious that the larger the head size, the greater the power potential. In fact, this is one of the places where limits have been placed on the dimensions of the frame, with anything greater than 135 sq. in. being illegal. Even under the maximum, it is possible for a frame to be illegal for tournament play if there are string segments that are deemed too long. An example of this would be the long-discontinued Head Ti. S7. The reason a larger head size generates more power, is because the string bed is able to deflect a greater distance, essentially storing more of the overall energy at impact. When the energy is redistributed, the strings lose a smaller percentage of their energy than the ball, and so a greater amount of the overall energy is subjected to a significantly smaller loss. Lowering the tension, and therefore stiffness, of a string will have the same effect because as the stiffness of the string bed decreases, there is a greater amount of energy stored in the strings at the time of impact.

We would like to talk next about the frame stiffness, which acts in a way that is opposite the stiffness of a string bed. In other words, the stiffer the frame is, the more powerful the racquet will be. So how do we justify this logically that a soft string generates more power, but a stiff frame is best for repulsion? It’s actually fairly simple, and it has to do with the recoil times of each product. No matter what string, no matter what racquet, the fact is that the strings rebound at a rate faster than the frame itself. In terms of time periods, the strings need approximately 0.004 seconds to rebound and send the ball off in the opposite direction. Even the stiffest frames currently available require nearly double that amount of time to rebound. This means that in the case of a racquet, a more flexible racquet means that a greater percentage of energy goes into flexing the frame. Most of this energy will not be returned to the ball because it will be already headed back across the net by the time the racquet rebounds to its original conformation.

Another area of the frame to look at is the shape of the frame itself, which will have a unique impact on the power level of the frame. In the past, frames were made in essentially only two styles, the box or square beam, and the more rounded, oval frame. An interesting thing happened when Prince came out with a unique technology that they called Morph Beam Technology, which combined the square beam in the throat, and an oval beam around the head. First, we must understand the flex characteristics of each shape. In general, the square beam tends to be more flexible, while frames with the rounded beam are stiffer. Even given this information, a rounded shaft like a Wilson Pro Open will rebound at a faster rate than a square beam such as a Head Prestige, regardless of a possible difference in flex. This is why you experience more power from a Babolat Pure Drive than an Aeropro Drive, despite the fact that the racquets are essentially identical in specifications other than the change in the beam shape in the throat area.

Even small things like the string pattern will affect the power level. This is because of the same phenomena and behavior as a difference in head size. A racquet that is designed with two different string patterns, will behave quite differently because of how the string bed itself will react. Just as we said that a larger head size allows the string bed to deflect more, thus storing a greater percentage of the energy, a racquet with a more open string pattern will act the same way. By effectively decreasing the stiffness profile of the string bed, it is possible to increase power.

All of these factors, and more, play a part in the development of a power profile for each racquet on the market. Due to the fact that frames typically differ from each other in many, if not all, of these aspects, it is not necessarily a simple task in determining a power level.