The following is a page from The Fault Tolerant Forehand, available in eBook and paperback formats on Amazon (click here).
The Fundamental Theorem of Tennis is two rules that govern every shot in the game. They are as follows:
1. The racket makes a 90-135 degree angle with the forearm
2. The racket strikes the ball in front of the body (or, in a pinch, in front of the forearm)
Any shot which follows these two rules will work. I should specify that I usually verbalize this rule as “a 90 degree angle” instead of “a 90-135 degree angle”, even though that’s often an exaggeration; many shots in tennis are played with a 135 degree angle, but I find that verbalizing and thinking about it as “90 degrees” produces the best results, since many students’ natural intuition is to play shots with a straight, 180 degree racket/forearm angle, and thinking about “90 degrees” prevents this.
Following these two rules puts the racket in a position to function as a trampoline off of which the ball can easily bounce. The forearm will facilitate velocity transfer back to the ball much better when the racket is perpendicular to it, rather than in line with it. Additionally, control over the racket is far superior in this position. There are many ways to rotate the arm-racket system while maintaining a 90 degree forearm/racket angle, and all of these will produce good shots. Further, there are many axes along which the racket can flick around the hand when cocked at roughly 90 degrees before starting the swing. This is especially necessary for shots performed while on the dead run. Mentally curing your racket to stay at 90 degrees will prevent you from attempting to adjust to balls by moving only the racket head without adjusting the entire arm-racket system; this incorrect, independent racket head movement elongates the angle between the arm and racket and causes you to lose fine control over the racket head’s movements.
As a last point of interest, as noted in the rule, in a pinch it’s not necessary to contact the ball in front of the body as long as the racket still hits the ball in front of the forearm. Think of full stretch volleys out to the side, or shots where the ball has bounced behind the player. In these cases, as long as the player is able to maintain some sort of an angle between the racket and the forearm and get the racket flicking forward by the time it strikes the ball, the ball will usually go in. There are many different ways to flick the racket around the hand. You’ll notice that good players on the full stretch often end up following through awkwardly in front of them, rather than around their body, because they’re focusing on generating any and all forward flick of the racket that they can muster from such a compromised position.
The Fundamental Theorem of Tennis is just one of many principles discussed in The Fault Tolerant Forehand, which will be released in March of 2021. Many pages from the book will be made publicly available completely free as they are completed, so don’t miss out! Great tennis is all about understanding what the game is truly about, and building from there. We don’t start with the joint angles, no “feet here, arms there, elbow does this, wrist does that.” Instead we start with a simple answer to a simple question.
How do I strike the ball to make it consistently do what I want?
July 15, 2021
I do not understand how to get in the 90+degree position. You have to lay the wrist back to get there?
July 16, 2021
Most players lay the wrist back to varying degrees, but it’s not necessary for the 90 degree angle For example, on the one handed backhand, just make a fist out in front of you and put the racket in it. That’s basically the grip.
July 20, 2021
My wrist will not lay back much, extension of around 40degress. Is the grip position that you mentioned for the 1hd backhand the same to be used on the forehand? A Western grip? Can I still achieve a whip action with a tight wrist joint? This has been a constant challenge to resolve on improving my forehand.
July 21, 2021
Great questions.
1. The more Western your forehand grip, the less your wrist will naturally lay back, and the more Eastern your forehand grip, the more your wrist will naturally lay back.
What’s important is simply that the wrist is relaxed. The small muscles in the forearm serve to stabilize the swing and prevent the racket from flying out of your hand, rather than serving to generate force themselves. The specific degree of wrist lay back isn’t an important detail.
2. No, the OHBH and forehand grip is not the same. For the OHBH, the most common grip is the index knuckle on bevel 1. For the forehand, the most common grip is the index knuckle on bevel 4 (called the semi-western forehand).
3. No, you cannot achieve the whip action with a tight wrist. If you try to force it, you’ll injure your forearm and elbow. The whip action comes from a relaxed wrist acting as a hinge while the bigger muscles in the body, specifically the hips and abs, twist you around and fling your racket out to the ball, then up and through it.
4. Relaxation is super tough to get a handle on. The key to relaxation is to learn how to swing slow and relaxed. When most people don’t want to miss, they tighten up. Instead, when you really don’t want to miss, try to just turn your body slowly, but stay super loose.
March 24, 2024
Using a lower grip size helps with wrist extension back. I used to play with grip 3 and when I changed to grip 2, that was a world of difference.
July 20, 2021
“students’ natural intuition is to play shots with a straight, 180 degree racket/forearm angle, and thinking about “90 degrees” prevents this.”
This is an excellent and very accurate observation! Just following up on my earlier post, does the 90degree angle relationship change to 180degrees when the swing gets to the “out” vector?
July 21, 2021
Very rarely, but on completely flat shots, sometimes. Most of the time, lots of the rotation is transposed to be about the forearm, creating the “windshield wiper motion.”
On a shot that’s completely flat, though, where the racket is swung totally level, it is possible that the wrist would go through 180 degrees, before going into flexion in the follow-through.
I should stress that this is *only* true on very explosive shots, and only true for players who are experts at staying extremely relaxed with their arm and hand.
For beginners, they should really never have a 180 degree racket arm angle, and they should envision tennis as moving the entire 90 degree racket arm system around the court and through the ball.
July 21, 2021
Thanks for the helpful replies. I just bought the book, had trouble putting it down! 😀 Lots of really great points building clarity around this very challenging and very poorly taught stroke. Another coaching cue Hall of Shame candidate is the gravity drop “C” loop! Perhaps the platinum medal 🏅
Agree, the relaxation part of the stroke is hugely challenging. Breathing tip is gold. I trained earlier today with a focus on Rule 1 of the fundamental theorem and noted how difficult it is to maintain the 90degree angle as the swing speed increased using more hip/trunk twist to whip and flick the racket. The loose wrist and forearm we’re going crazy. Agree with your point about swinging slowly at first. It’s challenging to control the racket face angle for fault tolerant contact at impact. Any further tips on this are greatly appreciated.
Re points 3 and 4 in your reply, for clarification, by the hinging of the wrist, are you referring to extension and flexion movements of the wrist joint? Or the radial and ulnar deviation movement? Or both. The wrist moves in different planes and makes controlling the racket angle challenging. Is is ok for a loose wrist to move freely in the swing in the ranges before and through contact? Getting the correct wrist feel sure is a battle. I have a bad habit of actively snapping the wrist to move the racket faster into contact. Retraining this is fun but challenging. The twisting concept is very helpful in that regard, as is the drop feed training.
Thanks again for the book, the website, and these replies. Also joined the mailing list. 🙏
July 22, 2021
Great, I’m so happy it was helpful! Yes, the “C” loop is another one that’s extremely misunderstood. On some forehands, the swing path does resemble a C, but that’s more of a coincidence – aiming at the C shape itself is akin to putting the cart before the horse.
With respect to the 90 degree angle – I wouldn’t worry about it on your forehand. As long as the wrist isn’t actively participating in the swing, and the hips and abs are the primary drivers of your racket, you’re probably fine. Every player’s wrist angle does completely unwind *in the follow-through*, so that angle will not remain static as you swing. If you watch a high fps slow motion video of your favorite professional player, you’ll typically see that the 90 degree angle is created as the racket lags behind the hand, and then maintained for most of the racket’s forward whip, and then finally straightens out and subsequently goes into flexion (non-volitionally of course) after contact.
As for the anatomical descriptions of the wrist action:
1. The wrist is brought into extension (passively) by the weight of the racket, which wants to stay at rest, but is pulled forward by the hand. It typically remains in extension until after contact (again, not by conscious effort), although many players’ wrist extension unwinds by 15-45 degrees throughout the swing.
2. Both radial and ulnar deviation occur during the stroke, but the degree of each depends on your forehand grip. These shouldn’t be attempted consciously.
3. A lot of the “wrist rotation” is actually the hand, wrist, and forearm all rotating together. Take your racket and pretend you’re wiping a window with it. A lot of the rotation on the forehand is this motion.
4. “Snapping the wrist” using your forearm muscle will actually slow down your swing, and over time may give your forearm and elbow an overuse injury.
Here’s a video I’ve referenced before (unaffiliated) that explains the wrist’s role as a hinge quite well: https://www.youtube.com/watch?v=k_iLAQnOsRY
July 23, 2021
Really appreciate the helpful feedback! I’ve seen that video, it’s quite well done. I don’t think that they address wrist flexibility enough though and it’s impact.
Because my wrist is so tight (barely 40 degrees extension and that is with tension) I have trouble forming/maintaining the 90-135 degree racket/forearm relationship during the explosive part of the forward swing into contact using an Eastern grip. Centripetal force makes my wrist flop into neutral and some flexion at contact. My wrist feels relaxed only in a continental grip unfortunately. But it also feels somewhat relaxed in a Western grip. I learned to hit a slice forehand, county grip when I started playing and learning/ generating topspin has always been a nightmare. I’m convinced that having a wrist extension flexibility range of at least 70degrees is essential to hitting a Fault Tolerant forehand.
Have you ever coached a player with a restricted, tight wrist and found ways to overcome that liability? Recommended grip and progressions? I tried the window wiping exercise and the racket face angle changes when I do this and my elbow hinges. I’m unable to maintain the same hitting arm position during my swing. What this suggests to me is that I’ve developed the habit of adjusting my arm to the ball to compensate for a tight wrist.
Appreciate any suggestions/recommendations.
July 23, 2021
I haven’t worked with a player with a anatomical wrist extension limitation before; that’s interesting. I think your instinct is right on: try a full western grip. This requires the least amount of wrist lay back of all the grips.
You can try modelling your stroke after Iga Swiatek, a player who uses a full western grip while still staying extremely relaxed and creates tons of racket whip through the hitting zone.
July 23, 2021
Just another quick addition, I’ve noticed on video that near contact my racket face opens up before contact, even in a strong Eastern grip. I suspect my wrist has something to do with this.
Also, meant conty grip, not county lol 😆
July 23, 2021
One of the only reasons I have students change their forehand grip is if their swing looks natural, but their racket-face is too open/closed at contact. In that vein, I think your desire to try switching to a Western grip is well founded. If it seems like your string angle is always too open by contact, then it’s definitely a good idea to play around with a more extreme grip, such that the same motion with the rest of the body produces a proper string angle.
July 24, 2021
Thanks, moving towards Western is the plan. Yes, my wrist situation is the exception (lack of extension) however it’s not uncommon, especially as one gets older. Interestingly, my left wrist is normal.
I’m able to make almost a right angle between the racket and my forearm. From reading and rereading the book, I realize that I’m breaking Rule #1, allowing my wrist to straighten and losing that range of acceptable forearm/racket angle of 90-135degrees. In all my years of playing, not one coach ever picked that up. I’ve not been throwing the proper hitting arm system at the ball and maintaining that structure through contact. I’ve been improvising with my arm and wrist, and often not hitting out in front.
Really enjoying the book and finally understanding the stroke at a much deeper level. I’m sure this will translate to a much improved stroke in spite of my wrist extension limitation. It’s interesting that you’ve mentioned joint angles are not as important as they’re sometimes made out to be.
July 24, 2021
That’s really cool that you noticed you are improvising using your forearm muscles. Are you the kind of person who, in order to strike a low volley, straightens the racket-arm angle out to push the racket head down? If so, very quickly after practicing with the new 90 degree paradigm, you should quickly find a new level of feel, and fine control over the racket head, that seemed totally foreign before.
July 26, 2021
You’ve read me pretty good! 😂…..yes, I do indeed straighten my arm angle for low volleys …..and pretty much all shots. I’m going to blame this on a tight wrist joint LOL. With volleys however, it’s easier to relax the hand and wrist in a continental grip.
If you ever saw MacEnroe hit a forehand, you would not see any lag and whip in his stroke because he hit it with a continental grip, same with Jimmy Connors, and many others, especially serve and volley players of that vintage. It locks out the wrist. You may want to test and confirm this for yourself. Would be most interested in your opinion. Can you get lag with a continental grip?
Just to clarify, the wrist remains in extension until after contact (re your point #1 earlier.
Regarding the “out vector”, from page 95
“The goal is to orient the racket-arm-wrist system such that the racket face rotates through contact roughly about the axis of the forearm, so that the string angle isn’t dramatically altered by the rotation. This typically means holding the racket with a relaxed, neutral wrist, and swinging diagonally up to the ball”
I’m confused about the “neutral wrist”, if I try to replicate this, the arm angle goes to 180degrees. I thought we need to keep the 90degree angle and the wrist laid back through contact…..or is this for beginners? The Federer images on page 96 show his wrist laid back and then it looks neutral at contact.
July 27, 2021
If you watch tour level forehands, 135 degrees is typically about the most obtuse angle you see at contact. It’s fine for the angle to open up from 90 to 135, but if it’s opening all the way to 180 before contact, your contact point is probably off. For most people, a neutral wrist makes a roughly 135 degree forearm-racket angle.
July 27, 2021
Thanks, I’ll be focusing and practicing maintaining that angle. I’ve been using the PermaWrist training device. It definitely helps maintain the 90-135degree angle. Have you ever used something like this with one of your students?
Forehand practice with the PermaWrist tennis swing training aid
https://youtu.be/RtVcK5YIJ7s
July 28, 2021
I haven’t used it before, but I suspect a strong evangelist for it could definitely convince me it’s worth it.
October 10, 2022
Rule 1 states: The racket makes a 90-135 degree angle with the forearm.
When is that? Before the forward swing as the Fed photo shows or at contact? I’d appreciate some more explanation about this rule.
I’ve just bought your book and am really enjoying it!
October 13, 2022
In general, at all times. Ready position, preparation, forward swing. Having your wrist in slight extension, and maintaining a 90-135 degree angle with the forearm will help give you control over the racket head. It will prevent you from using your forearm muscles to manipulate it, which won’t work.
The idea is that, on every full swing, you are essentially throwing your entire racket-hand-arm system through the ball, nut just the racket itself. On every touch shot, you are manipulating the entire racket-hand-arm system to deflect the ball to your target, not just the racket itself.
Hope this helps. One final caveat – on full swings, the grip should be loose, and the wrist allowed to extend. This angle often unwinds on a forehand for example. This rule is a starting point, especially useful for beginners who wave the racket around like a fly-swatter.