Radar Guns 101

In this post, we’ll move forward from our ongoing discussion of talking about stroke speeds (or the lack of stroke speed, as the case may be) at the various levels of US Tennis to talking about a more basic issue: how to properly measure your stroke speeds in the first place.

The first thing you need to do is to measure your stroke speeds accurately. To measure your stroke speeds accurately, you need to get your hands on a good quality radar gun and understand how to use it properly.

Over the past two years, I’ve had the opportunity to use a large variety of radar guns from every price point that’s currently available from the under-$100 “budget” guns (i.e. Bushnell Speedster II) to the $1,400+ high-end guns from JUGS and Stalker. What I’ve learned from using these guns is that as long as you’re willing to spend at around $200 to $300 for a mid-price radar gun, there isn’t a noticeable difference in performance among the various brands, or between guns from different (i.e. higher) price points.

The price for radar guns is more-or-less open ended, and the more you pay, the more features you can get (direct download of data to your laptop, software analysis for the downloaded data, etc.). But the features that are available in the mid-range guns are more than enough for the purpose of getting accurate stroke speed measurements.

In my experience, you will only run into problems if you go the “budget” route and buy the lower-end guns such as the SpeedTrac/SpeedChek (the little black radar box you place in front of the net) or the Bushnell Speedster guns. The SpeedTrac/SpeedChek has improved since its original introduction in the mid-1990s, but when I use the SpeedTrac/SpeedChek side-by-side with a trusted mid-range or high-end radar gun, there is way too much difference in the measurements between the SpeedTrac/SpeedChek and say, the typical mid-range radar gun for me to trust the readouts of the SpeedTrac/SpeedChek.

IHMO, say no to the SpeedTrac/SpeedChek in all its incarnations because who knows what it’s measuring.

Likewise, I haven’t had a good experience using either the Bushnell Speedster guns—either one, Speedster I or II. The problem for me with Speedster I was that it couldn’t measure speeds over about 105 MPH very accurately (which doesn't fly when you work with high level competitive players who can serve over 110 MPH) and of course, when I read the “fine print” of the Speedster I specs, sure enough, it said that the measurement range topped out at 105 to 110 MPH for tennis.

Speedster II supposedly possesses improved technology compared with its ancestor, but still doesn’t seem to measure speeds over 110 MPH with great consistency or accuracy.

Therefore… IMHO, say no to the Speedster as well until further notice.

So, what radar gun do I recommend that performs without going overboard with either price or features?

The radar gun that I’ve found that has the best combination of performance and price/value is a relatively new introduction to the radar gun market called the Tracer SRA-3000 radar gun manufactured by Sports Radar, Ltd. (Homosassa, FL).

In side-by-side measurements with my high-end Decatur radar gun and a friend’s brand-new JUGS R1005, the Tracer, Decatur and JUGS guns perform identically when it comes to accuracy and consistency. The biggest difference between these two radar guns is that the Tracer is cordless (it runs on 6 AAA batteries!), and is much lighter than the Decatur (my Decatur is corded to a rechargeable battery stored in its carrying case).

The other difference between the Tracer and the Decatur and JUGS guns is the price. You can get a Tracer for around $180 retail, whereas the Decatur and JUGS guns will run you a minimum of $700 retail (new). That’s around a $500 difference in price for a radar gun that performs to the level of the “luxury” guns.

The performance and value of the Tracer that I’ve experienced is the reason why we decided to offer it for sale on the TennisSpeed website. It performs at a high level for a great price. What more can you ask for from any product?

OK, so now you have some idea about what the various radar guns on the market offer… So now you may be wondering how to use that radar gun to measure your stroke speeds.

Using the radar gun to get accurate stroke speed measurements is straightforward enough…

1. Mount the radar gun on a tripod (make sure you have a tripod mount on your gun… The Tracer has one, does yours?) to ensure that the gun itself is consistently aligned for each measurement—this makes for the most consistent measurements.

2. To get the most accurate measurements on groundstrokes, place the radar gun behind the contact point and place the tripod in straight line behind the intended flight of the shot. Make sure to set the height of the radar gun at the intended contact height of the stroke (i.e. if you intend to make contact at waist height, make sure the gun is also set on the tripod at waist height).

Therefore, if you want to measure the speed of your down-the-line forehand, a simple way to check that you’ve placed the radar gun in a straight line directly behind the path of the shot is to point the radar gun toward the area of the court where the forehand will land (Figure 1).

Figure 1. Radar gun positioning for down-the-line forehand (gun positioned in a straight line behind the path of the shot).

3. To get the most accurate speed measurements for your serve, set the height of the gun as high as your tripod allows. Place the tripod behind you in the same line as your hitting shoulder. Similar to the speed measurement for your groundstrokes, align the radar gun itself in a straight line directly behind the intended flight of your serve to obtain the most accurate measurement (Figure 2).

So, if you want to measure the speed of your slice serve, a simple way to check that you’ve placed the radar gun in a straight line directly behind the path of the shot is to point the radar gun toward the area of the service box where the serve will land in the service box.

Figure 2. Radar gun positioning for slice serve (gun positioned in a straight line behind the path of the shot).

When you follow these 3 simple steps, measuring your stroke speeds becomes a breeze.

Maybe now you are wondering about which strokes should you be measuring…

I have been measuring maximal serve and groundstroke speeds for my players in the same way the WTA measures its players to create its “Power Index”. I have been measuring maximal (and average) forehand, backhand, first serve, second serve and overhead speeds (of balls hit into play, of course!) in both training and live matches.

I have also been measuring so-called “rally speeds” where I measure the ball speeds during “neutral” groundstroke rallies (neither player is in an attacking or defensive mode/position). The “rally speed” of a player tells me a lot about what tactical options are available to a given player. And yes, there is a great difference in rally speed when comparing the various levels of competitive tennis from juniors and high school varsity tennis to college and professional tennis.

The difference in “rally speed” is quite similar (among US players) to the differences in serve speed that we’ve been talking about at some length in recent posts. That is, there is about a 25 to 30 MPH difference in rally speed between juniors and professional players.

To sum it up, go get your hands on a decent radar gun and remove all of the myth and mystery from your game. Measure your stroke speeds and create your own “speed profile”: average speed of your fastest forehand, backhand, first serve, second serve and overhead. Now you have a way to compare yourself to other players with known speed profiles to see where you really stack up…

Then, measure your “rally speed”, and when you finally look at the numbers… It will be a number that probably won't be keeping Roger, Rafa and Andy awake at night.

Don’t be surprised when you find out that your speed profile is well, more like a “slow profile”. Get it?

Starting with my next post, we’ll be getting into what you all have been waiting for…

We’ll start talking about how to increase the speed of the various strokes from a technical and conditioning perspective. And I’ll begin talking to you about one of the special projects I’ve been working on recently that has truly blockbuster potential in changing the way tennis technique is taught by coaches and learned by players.

So stay tuned…

TTFN!

Informal stroke speed survey of US tennis-Postscript

After the last post where I reported stroke speed measurements for high school varsity tennis players, I received a comment from a reader who raised some interesting questions that I felt would make the basis of an interesting post and becoming a starting point to share some other interesting stroke speed-serve speed, specifically-“phenomena” with you.

The two main questions raised in this reader’s comment were as follows:

Q1: You mentioned the wide range of skills among the high school players you measured. In a future post would you be willing to break out your data to show the difference in ball speeds between the couple best players and the run of the mill HS player?

A: The average fastest serve for three 5A State singles (#1 to #3) champions was 104.7 MPH.

The average first serve (all serves combined) was 94.5 MPH.

The average second serve was 73.9 MPH.

The serve speeds of these State high school singles champions are comparable to the speeds demonstrated by the typical Nationally-ranked 18-and-under junior boy (see the post titled “Memo to American college and junior players: Find another 30 MPH ASAP!) whose average first serve was 91 MPH and average second serve was 71 MPH.

Q2: Also, how much variance is there in the Division I ball speed data? Having measured, using a RADAR gun and video analysis, the serve speeds of several Division I male players (from one team), I'm surprised that the average first serve speed you found for Division I players is just 90 mph. My measurements found first serves to be on average more than 10 mph higher than that. My measurements were in practice, though, and not in competition so that might explain much of the difference. For instance, the players were simply hitting hard first serves, not mixing up the speed and spin as they do in matches.

A: The way I measure serve speeds, I record the speeds of individual serves and note what type of serve (flat, slice, topspin, or kick) was struck. So, when I report the average serve speed for either first or second serve, the speeds of all serve types are lumped together in that figure. So, on first serves, the faster flat serve speeds are averaged together with the slower slice and topspin serve speeds.

To address the comment, if we consider the average fastest serve speed for 1^st serve for the D1 players I’ve measured, that average fastest 1^st serve speed is comparable to the serve speed measurements made by the comment author (which I am now pretty sure that he measured the average fastest 1^st serve speed) :

102.4 MPH (speed range was 81 to 120 MPH, mine) versus 100 MPH (his)

What’s also interesting to mention here is the trend I’ve noticed in the speed differential between the different serve types, i.e. flat versus slice and flat versus topspin/kick serves.

What’s interesting is that the speed differential between the different types of serves is relatively consistent even between the vastly different competitive levels from ATP pros down to 3.5 to 4.0 high school varsity players.

What I mean by this is:

The speed differential between a flat and slice serve is between 15 and 20 MPH at every playing level from the top ATP pros down through the NTRP 3.5 to 4.0 crowd.

For example, Andy Roddick’s flat serve averages typically averages around 135 to 140 MPH whereas his slice serve typically registers between 117 to 12 MPH. The typical NTRP 4.0 hits his fastest flat serve around 85 MPH, and his slice serve averages around 65 to 70 MPH.

The speed differential between a flat and topspin serve is typically 20 to 25 MPH for all playing levels I’ve measured so far.

FYI, if you are wondering what the difference between a topspin serve and a kick serve is, the easiest way is to distinguish them is to observe the direction the ball moves after the bounce.

A topspin serve bounces straight ahead or slightly toward the middle of the court relative to the original flight path of the serve, whereas a kick serve bounces toward the side fence (for right-handed servers, the bounce is toward the right side fence and for lefties, it’s toward the left side fence).

The speed differential between a flat and kick serve is typically between 25 to 30 MPH for all playing levels I’ve measured so far.

Why are kick serves slower than topspin serves? The answer is because of the slight difference in the arm swing path between the two serves—the additional sidespin applied to the kick serve by moving the toss further overhead decreases the forward momentum of the arm swing slightly resulting in a slightly lower overall racket speed (and therefore, (s)lower ball speed).

So, based on this consistent speed differential between the four main types of serves, I can essentially predict what the serve speed “profile” of a player is based on a single serve speed measurement. For example, if a player hits a kick serve at 75 MPH, the fastest flat serve they can hit will be in the range of 100 to 105 MPH. And if a player can hit a flat serve at 105 MPH, their slice serve will range from 85 to 90 MPH.

Are there exceptions to this “rule” of serve speed differential?

Of course there are… And the exceptions are of course, those players who can hit the absolute fastest serves (into the service boxes, of course)… i.e. the Andy Roddicks and Ivo Karlovics of the world, that is…

Roddick, for example, in the match he played today in the Masters Cup against Davydenko, routinely hit his flat first serve around 230 KPH or 143 MPH and his kick second serve around 160 KPH or 99 MPH….

This makes for a speed differential of 44 MPH!

But, I think you’ll agree, that in terms of on-court effectiveness, that 44 MPH difference doesn’t really have the same impact on Andy as it would for many lower-level competitive players whose maximum first serve speed is maybe, on a really good day, around 90 MPH. These are the same players who, after missing the box with their “90 MPH bombs”, then follow up with a massive 46 to 51 MPH topspin, “get it into the box” sitter that “quacks” as it flies over the net, to avoid the dreaded double-fault!

So, to close out this post, here's a memo to those of you who are standing, lifelong members of “Club 46”:

1) In order to hit an effective spin (second) serve, you need to generate the same amount of racket speed as you would on your flat serve to create both the necessary spin (for control) and ball speed (so your serve doesn’t quack and get smacked into all corners of the court by the returner).

2) If you want to hit a relatively effective topspin or kick serve, you need to be able to hit your topspin/kick serve around 70 to 75 MPH (air speed) to generate enough height and speed after the bounce to prevent most players from smacking your serve to all parts of the court without conscience.

3) Of course, if you can’t hit your flat first serve around 100 MPH, there’s basically no way (given the laws of physics governing the universe we inhabit) you can generate enough racket speed to hit a 70 to 75 MPH topspin/kick serve. So, if that’s your situation, may I suggest you start training with the SpeedChain to help you develop that extra 20 to 30 MPH you need to reach “Club 100”?

TTFN!