3D Data Weigh in on Pro Tossing
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MASTER PRO CORNER 3D DATA WEIGH IN ON PRO TOSSING the first 3D motion analysis system on Plagenhoef’s data shows most of the a PC available to coaches and athletes: accomplished players were letting the The Ariel Performance Analysis ball drop 15 inches or less to impact. System (APAS). Employing the use of APAS technology Figure 2 James R. Shaughnessy USPTA Master Pro he first tennis book inclusive Tof tennis biomechanics, The Fundamentals of Tennis was authored by Stanley Plagenhoef Ph.D. in 1970. The book gives some quantified data on the strokes of many legends from the 1950s and 60s, e.g., Pancho Gonzales, And as Dr. Ariel later became my we analyzed and can share some Rod Laver, and Roy Emerson from live own mentor in 1989, his pioneering revealing data we have collected and match play. work has inspired my own work over processed from players contemporary Olympic athlete, Gideon Ariel the past 3 decades, in tennis and in 3D to Dr. Plagenhoef’s collection.(Fig 1) studied with Stanley Plagenhoef motion analysis. Utilizing the SCiO 3D Sports and advanced to earn PhDs in both The goal has been to develop Library we studied twenty-first serves exercise science and computer science, teaching systems designed to collect, from tour matches that were aces and to win the International Society of process and employ live 3D data at or winners from seven male players Sports Biomechanics most prestigious every level that will be beneficial to who have been ranked #1 on the ATP lifetime achievement award. tennis coaches and players. tour, won Grand Slams, won Master’s During his career, employing Most recently, we have analyzed a 1000 events, or served 149 mph. Also his expertise in computer science topic, contentious since the inception studied were serves with the same coupled with the skills learned from of tennis – HOW HIGH TO TOSS criteria on fifteen serves from 8 Plagenhoef, Ariel went on to invent THE BALL WHEN SERVING. contemporary players from the WTA. (see table above Fig 2) Figure 1 In the SCiO Lab we ran statistics on racket tip velocities, the distance of ball drops to impact, vertical ball velocity and outgoing ball velocity on the contemporary players and their tosses. Anatomically there is a 4.5-inch significant difference in the average height of male vs female players (p<.05). Therefore, we broke the data into a male and female group for analysis. There was a significant difference in the average drop of toss from the 48 - USPTA ADDvantage Magazine — May 2019 MASTER PRO CORNER ball’s peak height to contact between that tossing higher is productive. In purpose of the high toss is to allow one elite men and women professionals further reflection one might question, to better load the body than a low toss, (p<.001). It followed that we should however, why one would want and the purpose of loading the body look for the advantage or disadvantage topspin? Topspin is productive for is to swing the racket swiftly upward, of the toss difference. consistency. Topspin curves the ball and the racket is not swinging more One argument I often hear when downward. Topspin gives a player a swiftly upward, the argument that a coaches tell players to toss higher is,” larger window over the net in which higher toss better loads the body fails. the player isn’t contacting the ball to be successful and topspin in most From our data we were able to high enough”. cases causes a trickier bounce. The confidently determine a strong The data in this study showed greater downward velocity on the ball correlation of success when male and however that, there is no correlation created by a higher toss theoretically female professional players impact between the height of the toss and the gets a little more topspin on the ball. the ball at 1.5 times their height height of ball - racket contact in the But, should we consider the trade-offs (p<.001). And comparing our two men’s group, the women’s group, or in required to get this small amount of charts, we see the lion’s share of Grand combined grouping. extra topspin? As an example, let’s Slam Championships are won are The take away is that: tossing the compare a serve by Dinara Safina and by players whose ball tosses drop a ball higher does not mean the player Venus Williams. maximum of 20 inches. will impact the ball higher. Safina’s toss drops 58 inches to In conclusion our study using data Another argument I hear for tossing contact. Venus’s drops 16. Safina’s from Roger Federer, Rafael Nadal, higher is that “you will get more ball arrives at impact going down Novak Djokovic, Pancho Gonzales, power on your serve.” (See my article 12.01mph while Venus’s is going 6.4 Rod Laver, Roy Emerson Serena in Tennis Industry Sept/Oct 2018 mph. Depending on the strings and Williams, and Maureen Connolly has page 48, “A New Direction for Racket the overall coefficient of friction, shown agreement that tossing higher Head Speed” for an explanation on the Safina might gain a little topspin will not facilitate hitting the ball misuse of the word power). here. What is the price? Safina’s towards your target with more speed. Coaches tend to use two reasons for toss must travel 6.5 feet farther than Tossing higher will not give you an insisting higher ball tosses give more Venus’s. If we assume the racket has advantage in upward racket velocity ball speed toward the target. First, the a nine-inch vertical area in which the to cause greater topspin. Even though ball is coming down faster and it will players can meet the ball on the string small gains of additional topspin due go out faster. Second, the higher toss bed, the ball will be in this region 79 to friction will occur when tossing will give more time to load the body. milliseconds for Venus compared to much higher, it will cost you increased Research at the SCIO lab at Racket 42 milliseconds for Safina. That puts exposure to wind, require you to be and Health 91 in Tulsa shows there the ball in Venus’s strike zone almost very accurate with a riskier and larger to be no correlation between higher two times longer. toss distance and cause a need for tosses and outgoing forward ball To check the validity of second your timing to be substantially more velocity. reason, we checked the upward precise to make solid contact. There Another commonly heard argument velocity of the racket tip which is are other kinesiological advantages to for tossing higher is that the player correlated with topspin on serve tossing lower not discussed. However, will get more topspin. There are two in other research. We found no when it comes to the toss, historic and alleged reasons. First. it is alleged correlation between toss height and contemporary 3D data reveals less is that the increased downward velocity upward racket tip velocity. Since the more.* of the ball will cause it to scrape against the strings faster creating more topspin. Second, that there is more time to load the body, therefore, James R. Shaughnessy MSS, CSCS, is a USPTA Master Pro specializing in the increased ability to swing up stronger application of sports biomechanics to elite tennis players training at Tucker Tennis with the racket and thus get more Academy a USTA Regional Training Center Racquet and Health 91 located in Tulsa. He topspin. is an award-winning professional with 30 years of experience as a speaker, researcher, The first reason alleges you will analyst and consultant in tennis biomechanics, 3D motion analysis and computerized get more topspin by tossing the ball exercise prescriptions. He is the founder of SCiO 3D Sports. Special thanks to Hank higher and therefore, tacitly concludes and Molly Pellegrini who make this work possible. June 2019 — USPTA ADDvantage Magazine - 49 .