More Shot Charts

I'm curious about what sorts of shots players hit, the ball speeds and spins, the heights over the net, the depth, where they contact the ball, is the ball rising or falling into their strike zones, are they hitting near the lines, aiming for backhands, and on and on.

My friend Brian Gordon is interested in how players hit the ball, their mechanics.

Mine is a distal focus. His is a proximal focus. I've written about the distinction (see here and here). Shot charts are part of the distal picture. I just came across some more shot charts today watching Nadal vs Kukushkin from Monte Carlo. The Tennis Channel was kind enough to put up a couple. I paused my DVR and took some pictures.

Here is Rafa's first set shot chart:

And here is the same thing for Kukushkin:

It's a bit hard to see, but the little dots are colored red, yellow, and green. The red dot means the ball had 3,000 rpm or more. The yellow dot means the ball had from 1,500 to 3,000 rpm. The green dot means the ball had less than 1,500 rpm.

I see only a couple of red dots for Kukushkin and a couple of green dots for Nadal. Rafa's diagram is red and yellow. Kukushkin's is yellow and green. Not surprisingly Nadal won the set 6-1. Spin to win. They said that Rafa's average spin rate was 3,200 rpm. Kukushkin's was probably half that.

For comparison I'll repost a shot location chart I made from a point Borg and Vilas played in the 1970s at the French Open.

As an old-timer who was told to keep the ball deep, I'm fascinated by how many balls all four players hit that landed in the vicinity of the service line and how few balls landed near the baseline.

Safety appears to be a higher priority than depth.

Also of note is that maybe with the exception of Vilas's shots (the top of the chart above), the balls rarely landed in a semi-circle behind the T. That's referred to as the semi-circle of death. If you're playing a good player on clay it looks like a good idea to avoid that area.

However, I know some pretty good players who wear that area out and dare people to beat them. Those players don't play on tour, to be sure, but they play at a pretty high level. I used to think hitting the ball near the T was tennis suicide. I'm no longer of that opinion. Depending upon how well you run and defend, you may be able to survive against a lot of players hitting the ball into the safe middle of the court.

Pushing, Pulling, Throwing

My earlier post, To Push, raises the question of the difference between pushing and pulling. I think that hitting a tennis ball, especially on the serve and the one-handed forehand, is a throwing motion. I think throwing motions are mostly pulling motions as opposed to pushing motions.

Getting your weight into a throw is definitely good advice, so perhaps I'm a bit harsh in my condemnation of getting your weight into a tennis forehand. But we don't lean on things we pull. If anything, we lean away from them, don't we? If I'm pulling a wagon to the north, I get to the north of the wagon, attach a rope or a chain, and pull to the north, away from the wagon to my south. That's the definition of pulling. To push it, I'd get behind it, to its south, and push on the wagon itself toward the north.

In thinking about this issue, I'm reminded of a category of baseball pitchers who essentially push the ball. Most baseball pitchers don't remotely push the ball. They throw the ball at speeds approaching 100 mph. They do this by pulling their pitching arm, hand, and ball toward home plate and the release point. One class of pitchers doesn't do that, though: the knuckleballers. Their motion is much more like a push. They don't rely on high ball speeds and spins. They rely on slow and erratic ball speeds and spins and paths to fool hitters.

I'm also reminded of golfers who generally pull with their left side if they are right handed. When I was younger all the golf instructions I heard were about how important the left hand was in pulling the golf club. It was even suggested that right-handed people should play golf left-handed so they could pull with their stronger side. My dad is left-handed but plays right-handed and has always been a very good ball striker. Maybe there was/is something to that age-old advice. I wonder if left-handed golfer Bubba Watson is right-handed. I know Phil Mickelson is right-handed.

Unfortunately for me, I'm not a strong puller. Maybe that's why I don't throw a ball very hard or hit a golf ball or a tennis ball very hard. In the weight room I'm much better at the pushing exercises than I am at the pulling exercises. Luckily my legs are pretty strong and we push with those even when we pull with our arms, so I'm not as bad as I might otherwise be. Thank goodness athletic moves start with a push of the legs against the ground or I'd hit the ball even slower than I do now! Yikes.

Anyway, as I told Alexandra in the comments on my To Push post, I think the best way to think about serves and one-handed shots in tennis is to try to throw the racquet through the ball. I think that's the way to maximize racquet speed.

Bubba Watson

"Bubba will pridefully tell you that he's never had a lesson and never studied his golf swing on video. He is truly the natural." – Jim Nantz, CBS 2012 Masters telecast

Huh. That could never happen in tennis.

Right.

Coached Out of Him

"I'll concede Tiger Woods was a genius. It's been coached out of him." Brandel Chamblee

Brandel contends that Tiger is the first golfer to achieve the level that he achieved and then dismantle his swing and start over. And Tiger's done it twice. He won multiple major championships, retooled his swing, won multiple major championships, and retooled his swing again.

The jury is out on whether he'll win any more majors.

Is Tiger a coaching industry success story or a coaching industry failure?

You could argue both. I would argue that the biggest mistake in the history of sports is Tiger Woods' obsession with technique.

Coaching, Continued

I was talking to a friend last week about coaching. He is no longer in the business, but was a tennis coach for many years. I told him that I essentially just practice with the kids I work with and any coaching I do is incidental. I talk tennis with my tennis "students" just like I talk tennis with all my tennis friends. We discuss different ways to play, ways to hit the ball, what it feels like to compete, that sort of thing. I'm a tennis friend who happens to be pretty good still and has been through some of what they've been through. I don't consciously teach them, especially when it comes to how to hit the ball since most of them are in their teens and past the optimal stroke-development window.

That's a long preamble to what my friend said that struck me as b.s. He said that a player who was coached would improve twice as fast as someone who was not coached. He couldn't possibly have any basis in theory or practice that could back up such a statement. Why not twenty-five or fifty percent as fast? Why not ten times or one hundred or a thousand times as fast? Why twice as fast? That surely had to be made up.

As I've probably mentioned on this blog before, I'm not sure that in aggregate, in tennis, at least, that coaching doesn't retard development. If coaching can have an effect, we must accept that the effect could be negative. From what I've seen of tennis coaching over the past thirty years, I'd wager that the net effect has been negative, but that's a different post.

I'd like to assume that coaching can help, but that coaching needn't come from paid coaches. I think players can coach each other. I propose that players in most games learn from each other. I'm thinking about the modern games like video games or X-games stuff like skateboarding, snowboarding, etc. What about frisbee? Who coached people to toss frisbees?

Humans don't learn in vacuums. The choice isn't between coaching/teaching and having to discover something in isolation. Humans seek out other humans and learn from them. They watch, they experiment, they listen, they ask questions, they explore. Coaches can be part of this. But the main ingredient in improvement in anything is the desire to improve, the desire to experiment, the desire to try and fail and try and succeed. And to repeat this process over and over and over and over until normal people have moved on to something else.

So long as the environment provides adequate feedback, it's the person who fanatically practices whatever skill he wants to master who will succeed. Part of that fanaticism will frequently lead a person to seek out examples of how to do it better.

Some rare people will discover ways to do things that are better than anyone has every done something in the past. You can't coach something that hasn't happened before.

Mechanics

How important is technique in tennis? How important are mechanics? The two are not quite the same thing, but both are important. I don't, however, think that either is as fundamental as one other skill, namely hitting the ball cleanly, whether with spin or without as you choose in various contexts.

I think of technique as a broad term for how you do something like swing a tennis racquet, golf club, baseball bat, or play the piano, drive a car or perform any task. I'm not a linguist, but I think the term comes from the Greek word technê.

Mechanics, on the other hand, refers to Newtonian physics which deals with forces acting on the body and forces generated by the muscles of the body. When we talk mechanics, we're talking about how efficient your technique is in producing racquet speed, primarily.

So people can have better or worse technique and better or worse mechanics. The two are interrelated but are not exactly the same thing.

Players with good mechanics use their neuro-muscular system efficiently. They generate the most racquet speed with the least effort. So how important is this to playing tennis well?

For the serve, it's darn important. Given that the timing of hitting the ball is fairly simple, mechanics almost totally determine the quality of a serve. Even with a fairly high toss, the ball is moving pretty slowly and very predictably prior to and at impact. So the eye-hand coordination needed to hit a serve well can be accomplished by most people over time.

Not so with forehands and backhands. If a coach feeds a ball to a player, then the eye-hand skill necessary to hit a ball well is not so different from a serve. If a coach stands in front of a player and hand-feeds the ball for forehands and backhands, then the eye-hand skill needed is probably less than for a serve. So this closed environment is good for isolating work on mechanics. But the world of tennis is very, very different from that hand-fed world.

Another skill is needed before the mechanics and technique will be of use. That skill is a perceptual skill. The player must learn to track and intercept a moving ball with a tennis racquet whose hitting area is roughly 45 cm from the player's hand. The hitting area of the racquet may be as large as 135 sq cm, but in reality the "sweet spot" of the racquet is much, much smaller than that. I don't have data on this, but if you can't hit the ball in an area of 20 sq cm or less I don't think you'll be much of a tennis player.

This 20 sq cm area must intercept the ball somewhere in front of, and off to the side of, your body, too, to be effective for most shots. Tennis balls don't arrive reliably and predictably in this "strike zone" in front of and to the side of a player's body. The player must move in response to the speed, depth, height and spin of the incoming ball to place the strike zone when and where it needs to be for the player to hit a solid forehand or backhand.

After this movement, the player still must time his or her stroke to get the 20 sq cm or less racquet surface area and ball to meet in that strike zone. The hitting surface must be angled properly to hit whatever shot the player intends.

All of this perceiving, moving, timing and aligning takes place in under two seconds for almost all levels of play. It takes about one second at the top level of play. Since human reaction time is at least 0.2 seconds, some of this movement needs to take place before the opponent even hits the ball.

Because of all this, I think it's safe to say that perceptual skills are prior in every way to mechanics and technique. Without the ability to judge the velocity and spin of the incoming ball, a player simply cannot use his or her wonderful mechanical technique to hit forehands and backhands.

This has become clear to me as I've experimented under different visual conditions. I'm blessed with poor uncorrected vision. Without glasses I see worse than 20-400. Thankfully with glasses and contacts, my vision is corrected to 20-20 or better. My poor vision, and aging eyes (I'm nearly 50 yrs old) allow me to experiment with sub-par vision and tennis. I play my best wearing contact lenses in bright sunlight. I play better with contact lenses than with glasses under all lighting conditions. I can hardly play at all without correction, though I can hit the ball a bit.

My technique and mechanics do not change as I go from contacts to glasses, from sunlight to artificial light, to no correction at all. But my skill level changes dramatically. I go from capable of hitting with anyone in the world, to not being able to sustain a rally from baseline to baseline above about 40 mph ball speeds as I remove my contacts and glasses. That's quite a drop off.

I'm not saying that technique and mechanics don't matter. Far from it. If you want to hit a 120 mph serve, your mechanics had better be good. If you want to crack a sitter forehand over 100 mph, your mechanics had better be good.

But if you want to play high level tennis, sustain rallies with ball speeds over 70 mph, then hitting the ball cleanly is much more important than efficiently generating racquet speeds. I've seen little girls with suspect mechanics rally upwards of 80 mph simply by hitting the ball solidly over and over again.

To Push

Here's how The Free Dictionary defines the verb "push":

push  (psh)

v. pushed, push·ing, push·es

v.tr.

1. To apply pressure against for the purpose of moving: push a shopping cart through the aisles of a market.

In tennis, "to push" is to simply put the ball in play with the goal of waiting for your opponent to miss. The term is a pejorative. Nobody wants to be called a pusher.

My question is, do we tennis coaches encourage "pushing" when we instruct a player to "get your weight into the shot"?

I think the answer is unequivocally yes. When a human pushes something, a shopping cart in the definition above, a door, a car, the human puts his or her weight into the task. The person exerts pressure by the arms and by body weight. So putting your weight into something is fundamental to pushing.

Swinging, on the other hand, which is what a tennis player should do in order to move the racquet quickly to hit a ball hard, does not involve "getting the weight into" the swing. A swing is a rotational movement (think hammer throw) where the swinger's weight is not necessarily, or even usually, moving in the direction person is swinging the object. In order to swing an object, force must be directed inward to keep the object from traveling away in a straight line. (see centripetal acceleration here)

So, pushing force is directed in the intended direction of movement. "Get your weight into the shot."

Swinging force is directed inward so an object can be swung in a circular path rather than along a line. So weight, if directed anywhere, is directed inward in a swing.

"Get your weight back" is a better instruction than "Get your weight into the shot" if you're swinging an object.

If you want to push something, then by all means get your weight into it.