...because I need the exercise, and apparently nobody else thought of it first... Homemade Tether-Tennis: It Really Works! A do-it-yourself stroke trainer you can build in less than an hour. Last updated 06/11

• Overview: What it is
• What it can and can't do
• How to build your own...and do it right the first time
• Sourcing or making tethered tennis balls
• Two-player options
• An idea for converting disused playground poles for tethersports
• A warning about hyperextension and repetitive-strain injuries

Cheap adult fun, and not a bad cardio workout, either

Playable? More than you might think. Here's my "tall" (14-foot) pole in action with a proper tennis racquet. When you really put some wood into the ball, this becomes a serious workout! To play the movie, right-click over the image and select the appropriate option.

A few weeks back, I had a hankering to get me a tetherball pole for my trailer's enormous front yard. While browsing the tetherball set (singular) at the local Canadian Tire (the only big-box of seven in town that even had a tetherball set), I also found the last of the store's "as-seen-on-TV" Hit-A-Way tennis trainers, designed for volley practice.

I had a brainstorm: the loop in the Hit-A-Way ball reminded me of a tetherball. The Hit-A-Way itself used tethers to keep the ball spinning around a pole on about the same plane, but perhaps I could use it to play "tether-nis" with a tennis or racquetball racquet. So I tied a loop at the bottom of the tetherball rope (soft, stretchy dollar-store clothesline rope) so I could loop the Hit-A-Way ball onto it, and added carabiner to the tetherball so that I could still use that ball if I wanted. It worked better than I could have hoped.

First, I attached the tennis-ball-on-a-rope to the tetherball pole. I worked beautifully as a stroke trainer...provided that I was able to hang the rope low enough (too high and I was always chasing overhead shots) and provided that I used a racquetball racquet. That was fun for about a week. Then I noticed that my landlord had a pile of extra 14-foot fence poles left over from an old paddock, and a posthole auger. The ground where I live is soft sand, so I was able to auger out a two-foot hole for a fence pole. I lined the hole with a layer of galvanized ductwork sheeting to make removal easier, nailed the rope onto the end of the fence pole, planted it in the hole, and within thirty seconds I knew I had hit upon something wonderful. No longer must I drive 20 miles to find a parking lot and a bare wall to practice. And this thing really, really works well...provided you've got the space for it, a pole long enough to provide good action, and a supply of looped practice balls.

The thing is, I got lucky...most of my first choices for rope, balls, pole, etc. worked out as well as they could have. But some things I had to figure out, and I realized early on that without a few basic pieces of information, it's very easy to create something that just isn't worth the time or expense.

A game platform for the kids, too...

If you've got kids, this is more than a trainer. It's a game platform. Tetherball becomes unbearably tedious past about the age of ten, but tetherball sets with ropes extending to the ground (which I recommend) make for great private volleyball practice, and you can add a second tennis-ball rope at a lower height to allow for better play by younger players. If there's a second racquet around, they'll eventually figure out competitive games of their own that go far beyond what tetherball offers.

...and a cheap, easy-to-manufacture tethersports option for inner-city playgrounds with disused poles

While batting the ball around one afternoon, I even figured out a simple little device that could be built in sheltered workshops which would allow this functionality to be added to any disused playground pole of eight feet or higher. Provided that users bring their own tethered tennis balls and tetherballs, this device will transform any unused wooden or steel pole to provide the same functionality of my "home version". I've even provided sketches of the device below to show anyone who's interested how it works, how it's made, and how it could be implemented on an urban playground.

I'm sharing this here because a Google search of homemade tennis trainers turned up nothing anywhere close to what I'm showing you here. This setup provides me with an experience very close to what I enjoyed in high school, when I had a three-storey gymnasium wall at the end of a high school parking lot as my practice space. In many ways, this tethered trainer is far superior to the brick wall. And since I got the formula right, I've been using this for at least half-hour a day, four times a week, and I'm a long way from being bored with it.

Here's my shorter 'racquetball' pole in action, showing just how quick and playable this little gadget really is. To play the movie, right-click over the image and select the appropriate option.

What I love most about this system is that it allows me to work on my stroke mechanics with a greater efficiency than any method or system that I've ever used. Get into a rhythm with some good velocity on a shorter pole, and you can take up to 30 comfortable strokes per minute. I know of nothing else that will allow you to work on specific mechanics or stroke smoothness at this rate. I've seen and felt the results, too. I wasn't a bad player in my teens, but I haven't played in thirty years. I got my old technique back in just four short days, and by the end of the second week I'd developed both my forehand and backhand to a technical level beyond anything I had as a kid. Whether that development translates to an actual court remains to be seen, but that's not why I use this. I find the challenge here is to train a smooth stroke into muscle memory, and my goal is reach a point where I can hit consistent, smooth strokes both backhand and forehand for a full half-hour. I'll probably never get there, but I'm amazed at how much I'm still improving...I was certain I'd plateau before the end of the second week.

It's nowhere near as effective for volley training as the "real" Hit-A-Way trainer. It's not really designed for serious tennis or racquetball training. But it really works well and gives you a real workout, provided the pole is tall enough for comfortable play (at least nine feet), the area isn't particularly windy (this can really affect the return rate and location of the ball), the area around the pole isn't crucial to your decor (gravel is good; your footwork can tear up a four-foot circle of grass in a single afternoon).

I can't pretend that it's anywhere close to an ideal racquet trainer. The mechanics of this are such that spin is largely meaningless, and any skill you acquire at aiming the ball will not translate to the court. But as a pure stroke trainer, this is a masterpiece of simplicity. You get the feedback of a quality hit, and perfect balance too...for every forehand stroke, you have to take a backhand stroke, and I don't know of any other type of tennis trainer that offers this advantage.

This isn't as useless for serve training as it might appear. You just won't get a clear idea of where your serve might have landed, although you could easily use a a long section of rope attached to the ground with a tent spike or two to create a makeshift serve trainer. The rope always interferes with the sense of accuracy; there really isn't a substitute for a bucket of balls on an actual court.

There was a surprising number of subtle choices during the assembly of this extremely simple gadget which played a huge role in how it performed, so I'll briefly go over the components and what I discovered about what works and what doesn't. Important aspects to consider are as follows, each discussed in the subsections that follow:

1. Pole location
2. Pole material, diameter and height
3. Digging the hole
4. Tether rope type
5. Tether length
6. Attachment type
7. Balls: This requires its own separate section

Pole location

This is one of the easier aspects of the project to get right, but you'll pretty much have to decide on pole type and height before you fix a location.

Here's my "tall" pole in perspective. This pole is planted two feet deep in a hole lined with galvanized sheeting for winter removal. It sits loosely, but it weighs enough that it doesn't rock much at all from the centrifugal force of a hard shot. I tried pinning the tether lower, and even added three feet to the top to get the proper height...twelve feet does it absolutely right for me.

Turf wear: Wherever you put this, keep in mind that your feet will be moving a lot. Gravel, packed dirt or sand, and asphalt are the best options. If you plant one of these poles on your lawn, be ready to sacrifice the grass on at least one side of the pole, because it won't last more than an hour or two with all the pivoting and twisting you do to set up shots. This is not quite as serious an issue for tetherball and volleyball practice, though, or if your kids will be the primary users and you require them to not wear runners on the lawn.

Swing diameter: You also need an area where your ball(s) can swing as widely as needed without hitting anything. With a twelve-foot pole height from the ground, you only need about sixteen to eighteen feet across at eye level, but at the full width of the swing, you'll need an area a full twenty-four feet in diameter to insure unimpeded use.

Ground type: Of course, if you can't dig a hole deep enough to adequately brace your pole, you're screwed. I live in an area where most of the topsoil is alluvial silt from an ancient river; below about eight inches, you hit yard after yard of soft sand. As a rule of thumb, you need a foot in the ground for every six feet of pole height. My tall 14-foot pole sits in a hole 2-1/2 feet deep, and it's really more than I need.
If you can't dig a hole, you can still set the pole fairly solidly in six to eight inches of topsoil by using a tripod or quadripod. Leave six inches of pole below the feet or bracing material to sink the pole into the ground, and a few tent spikes should be all you need to fasten a pole to the ground for this application. You'll be hitting tennis balls fairly hard, but they're fairly light to begin with. Tetherballs and volleyballs hung from nets will create a lot more strain. You can also use existing structures if you brace your pole properly. Note how my short pole is attached to my landing. All that holds this to the landing post is a pair of metal straps held down with 1-1/2" screws, and it takes all the pounding I can give it because the pole itself is sunk into the ground. If the pole was only attached to the landing, however, I'd have torn it out of its retaining straps with my very first use.
If your pole is heavy and needs to be removable, line your hole with something slippery. I know, that advice probably fits better in my sex section so make your little jokes and let's get on with it. Once you've dug your hole, line it with something like galvanized duct sheeting or a thickness of cut-up "crazy carpet". The galvanized sheeting in my large pole's hole allows me to install and remove it quite easily, in spite of the fact that I'm only 125lb and the pole weighs almost as much as I do. Once raised beyond a certain angle, the bottom of the pole slides along the sheeting and into place at the bottom of the hole. Without this lining, it would catch on the side of the hole, requiring it to be literally lifted into place.
The pole does not need to be rigidly fixed into the ground, although it does improve the action of the ball. My large pole is not firmly fixed, so it swings gently as I use it, which slows the ball down just enough to be noticeable, but not enough to bother me. Hell, my pole doesn't even stand straight up...it bends toward the shed at about a 3 degree angle. It doesn't affect play at all.

Pole material, diameter and height

Material: You'll probably end up using anything you can get your hands on. Naturally, the heavier the material, the better your results are likely to be. My short pole is a length of virtually unbendable 1" steel pipe. It flexes somewhat when used for stroke practice, but not nearly enough to interfere with the quality of play. My short pole even uses a 3-foot extension which came with my cheap tetherball set. The thin pole material used here is more than strong enough for use with tennis balls, but I was also surprised at how well it holds up to hard use with a much heavier rubber tetherball. My long pole, of course, is a very stiff cedar log. The stiffer the pole, the faster the return speed of the ball. For kids, or for racquetball racquet use, an eight-foot pole left over from a patio umbrella might be plenty. But my short pole turned out to be far too short for comfortable use with a tennis racquet, even the old style racquets with the smaller heads.

Pole diameter: If you remember tetherball from your childhood, then you know that the game depends upon the use of a fairly thick pole. The goal is to wrap the tether around the pole until the ball touches the pole, so the wider the pole, the fewer windings it takes to score a point. When building a racquetsports pole, thickness is less important than stiffness, because you'll be hitting the ball on your backhand for every time you hit it on the forehand.

Pole height: I cannot stress this too highly: always try to use the longest pole you are ever likely to need. Expert players may prefer a pole up to 18 feet in height. The secret is that you can suspend multiple ropes from the top of the pole and tie them off at different heights to test the action of a particular rope length. My ideal height from the ground is 12 feet; I've tried 15 feet and the ball return takes too long for my taste. Also keep in mind that the actual length of the pole has to include the section of the pole that you'll be planting in the ground..

Digging the hole

Be sure you can dig deeply enough: I was able to dig my tall-pole hole using a garden claw to loosen the top sod, and a post-hole auger to dig a 6"-wide hole down to two feet. If I had only been able to dig to nine inches or so, I would have attached some triangular braces to the pole up to about a two-foot height, and drilled holes along the ground end of the braces so that I could attach the bracing using tent pegs to reduce pole movement. If you can't dig very deep where you are, you'll have to improvise some sort of above-ground bracing to keep the pole from pulling itself out of the ground when in use. If you're lucky enough to have soft soil and a thin, stiff length of pipe, you might be able to sledge it into the ground without any digging at all.

BE SURE YOU CAN DIG SAFELY!: Nothing's buried near the driveway here, so I have no concerns over hitting tile or cabling. You might, so always know in advance just how deeply you can dig in any location where you want to plant your pole.

Hole depth and diameter: Hole depth should be one-seventh of the total length of the pole to insure long-term stability. You might be able to get away with less, but don't take chances with heavy poles that might be used by children. A heavy pole that pulls itself out of the ground with use could cause serious injury to a child or an adult. My large fencepost pole is literally heavy enough to kill someone if it fell on them the wrong way. Naturally the hole should also be slightly wider than the pole, but my fencepost pole is four inches wide at the bottom, and sunk into about a six-inch hole. Rather than tighten up the hole by filling it, I decided to use scraps of wood as wedges to hold the pole in place. They're all I need for a pole this heavy, especially since it doesn't have to stand perfectly straight for my purposes.

Tether rope type

I have literally tried over twenty different types of line on my tether poles, so I speak with some authority here.

The best stuff I found was 100-lb-test nylon-fiber utility rope which I bought at Wal-Mart. It wasn't cheap - $3+ for fifty feet - but it's thin, it's slinky and it's strong enough for tennis or tetherball use. It is about 1/8" thick unstretched (half that when stretched), however, so wind resistance slows the ball down somewhat with this rope. I tried a heavier clothesline rope (about 3/16" thick, unstretched; 1/8" stretched); it was certainly usable but the wind resistance was really noticeable. Rope this thick might be fine for tetherball, but it makes tennis-ball use impossible in anything more than a moderate breeze.

I believe the ideal choice (which I have not tried) would be 100-lb test fly-fishing line. It's braided, so it stretches a bit (this is important, as I'll explain in a moment), and it's much thinner than nylon rope, so there's far less speed lost to wind resistance when the ball returns to you.

Chain is not recommended for any purpose. Early in the 1970s, playgrounds were advised to use thin, smooth chain rather than rope for tetherpoles. It requires a lot less frequent replacement than rope, but kids would inevitably swipe at the ball and get their wrists wrapped tightly in the chain. I suspect a rash of broken wrists from this trend probably explains why tetherball poles all but disappeared from YM/YWCA playgrounds early in the 1970s. It is possible to use chain only for the top half of the tether, but this will create a weight imbalance in the tether that will seriously affect how it plays. I wouldn't use it for any purpose.

Plastic-coated wire clothesline rope: This should not be used where children will play with the pole either, because this too can cause wrist injuries. But it's interesting stuff for a racquetsports trainer, so you may want to try it. The lack of stretch in this rope forces you to make a perfect shot or the ball will bob and weave crazily, "knuckleballing" around the pole as it returns to you. I don't like this action, but I'd probably practice with it if I was a competitive player simply because this would be great practice for my reflexes.

Monofilament fishing line breaks too easily. High-test line (I wouldn't use anything less than 75lb. test) is too expensive for me. I tried a triple length of 25lb test monofilament line and it broke on my third hit.

Monofilament weed trimmer line behaves similarly to wire clothesline rope, and unless you can find something particularly soft and slinky, it's virtually impossible to find trimmer line that you can tie into knots that will withstand the forces you'll expose it to.

The rope used for racquetsports can also be used for tetherball, provided you're able to undo any knots you may need to tie in the rope to make the length more appropriate for tetherball, but you're better off suspending a separate, different-height tether specifically for tetherball use. You can even make your own makeshift tetherball by nesting a volleyball in an old basketball net, and tying the net to the end of the rope. Just be sure to wear gloves when you play...spiking a volleyball that's nested in a basketball net will definitely leave a lasting impression on your palm!

Always install two or more tethers the first time you set up your pole: When you install your first pole, I recommend fixing at least two or three different lengths and types of line to your pole so you can get a feel for what works without having to change tether lines all the time. Regardless of how you attach the tether, you can always affix three or four ropes on a tether pole without them affecting each other's performance. Just lash the unused lines to the pole with a shoelace or length of twist-tie when they're not in use.

Tether length

Seem like this should be obvious? It isn't.

Tethers used for actual tetherball should allow the ball to hang no lower than about two feet. Tethers longer than this will require a lot of bending and result in too many out-of-reach shots, making tetherball play frustrating and tedious.

Tethers used for racquetsports can be significantly longer. If it hangs too high, you'll never dig for a ball. If it hangs too low, it can bounce off the ground on shots close to the pole. You also need to account for the stretch of the tether when the ball is applying centrifugal force to it.

Correct length is a matter of taste, and may require some experimentation to set correctly for your needs, but here's what I've found:

• My ideal tether length is seven inches off the ground with the tether stretched tight. Seven inches is the length of a tennis ball plus the tethering loop. A tether of this length never bounces on the ground and gives me the best range of low "digs" and overhand volleys.
• I never cut the tether to length before planting the pole into the ground. Remember...you have to tie a loop into the ground end of the tether to attach the tetherball or looped tennis ball, so you'll need to account for this.
• My tall pole has three lengths of tether attached: my most-used tether is the longest. I have a ten-foot tether created by tying off a second line with a length of wire at about the ten-foot height; you can barely see it in the photo of the tall pole. I have a third tether at the eight-foot height which I only put into use when kids are visiting.

Attachment type

There are three obvious ways to attach the tether to the pole. Only one is the right way. You can either:

• affix a large nail or bolt into the end of a wooden pole and attach tethers around the nail or bolt,
• drill a hole through the end of a metal pipe and tie the tether through the drilled hole, or...
• attach an eyelet bolt and tie the tethers to the eyelet bolt.

Unless you can't find one when you need it, always try to use an eyelet bolt. The other two solutions both result in the pole end of the tether rubbing against an abrasive surface when you're playing. Eventually, that abrasion will wear through the rope, and when you least expect it, the tether will snap, causing the ball to fly through a neighbor's window, and odds actually favor the ball flying through your neighbor's most expensive window.

An eyelet bolt, by the way, is a bolt with a closed loop in it precisely for the purpose of attaching ropes and chains. Heavy (3/16" thick or thicker) eyelet bolts should be used for metal poles; heavy eyelet screws should be used for wooden poles. The heavy ones cost about two bucks each. If you have a choice, select the smoothest, shiniest bolt or screw that you can find. Never use an eyelet bolt less than 1/8" thick; this is probably too thin and easy to break for anything but the lightest recreational use by kids.

When you use a heavy eyelet bolt, either attached to a steel pipe with a nut-and-lock-washer or a krazy-glued nut, or screwed into a wooden pole, you have a non-abrasive surface that your rope can swing from without suffering any wear. You can even polish it or lubricate the eyelet loop slightly to further reduce abrasion.

The eyelet bolt should never be attached directly to the end of the pipe or pole. Instead, it should be attached at a right angle an inch or two from the top of the pole. When you attach the eyelet bolt to the end of the pipe or pole, the rope will rub against the edge of the pole, causing more abrasion. When installed an inch or two from the top, it only wraps around the pole...it never contacts an abrasive surface. And while this does have a very slight impact on the actual behavior of the ball, you'll be hard-pressed to notice it unless you're a serious competitive player. (If you are, by the way, all you really need to do is find some way to eliminate the friction which occurs when the rope contacts the top edge of the pole, perhaps with vinyl tape or a plastic cap of some kind.)

It may be hardly noticeable to all but the best players, but the position of the eyelet bolt affects the way the ball behaves. When you plant the pole with the eyelet facing you, you get a slightly faster but less accurate response than when the eyelet bolt is on the side of the pole facing away from you. I prefer the slightly slower but more predictable response of having the eyelet bolt on the far side of the pole.

If you have to fix the tether to the end of a pole, you can still get the same safety and response effects of an eyelet bolt by lashing down the rope an inch or two below the top of the pole. With a metal pole, you can lash down the rope using old extension-cord wire tied around the pole. This should keep it from abrading on the edge of the pole. With a wooden pole, simply pound a couple of nails halfway in on either side of the rope as it hangs from the top, then bend the nails over the rope. The heavier the nail the better, as long as you can bend it over the rope and it won't split the pole. Thinner nails will eventually pull free of the wood with repeated use.

A flying eyelet bolt can do much more harm than a flying tennis ball. Remember that the bolt will be exposed to the elements when not in use. Replace it annually; the last thing you want is a snapped corroded eyelet flying into the street or a neighbor's yard.

There are ready-made solutions available if you can find them, but homemade balls are a fraction of the cost. Here's a few homemade "tether-nis" balls. I used a 1/4" drill bit to create these holes; 3/16" is enough to get a double-width of rope through. Drill carefully! Well-drilled circular holes will last; rough-cut holes will cause your ball to split after a few really hard hits. Leave a large enough loop to fit the ball through, otherwise the smaller the loop, the lower the wind resistance. Before drilling pressureless practice balls, squeeze them to see if there's a stiffer seam somewhere on the ball. If there is, aligning the stiffer seam with the strike plane of your racquet will give you better response and the ball will last longer before going soft. Because these balls never scrape on the ground, the fuzz can last for weeks.

This whole adventure started with the discovery of the pre-looped Hit-A-Way balls. They promised to be surprisingly durable, but they only lasted a couple of weeks before the rubber began to split along the seams. That left me with a problem. I'd bought the last two Hit-A-Way balls in the area...how to source replacements?

I wasted nearly an entire afternoon spent trying to secure replacement Hit-A-Way balls with no luck. I did eventually find tethered balls from a different maker from holabirdsports.com on their Training Aids page, but I don't know how well they'll work. Eventually I remembered something from my late teens: the Tretorn ball. This was a heavier, pressureless tennis ball that I used because while they didn't have quite the same bounce as a new Wilson or Dunlop, they did last several times longer. A pressureless tennis ball would allow me to create my own looped tennis balls, and hopefully give me something that offered the same response as the pressurized Hit-A-Way.

What I didn't know at the time was that pressureless tennis balls are far more common today. Back in the 1970s, Tretorn were the only makers. Now, every major manufacturer sells pressureless balls as "practice" balls. Most big-box stores now carry bags (not cans) of a dozen stiffly-constructed practice balls perfect for use as tethered tennis balls. And I'm happy to report that when properly made, they last as long as the Hit-A-Way's (15-40 hours of play per ball), they lose very little response over their useful life, and they actually provide better response than the pressurized Hit-A-Way balls. It just takes a little time to prepare them, so it's usually a good idea to prepare several at once rather than one-at-a-time as needed. Here's how I did it, and I apologize for not having photos of the process...I've only done this once and wasn't sure it would work on my first six balls. It worked so well, in fact, that it may be next year before I need to make another ball.

1. I discovered early on that the Wilson ball has a funny characteristic. If you squeeze them from various angles, you eventually discover that at least half of them have "strong seams", a ring around the ball where it's harder to squeeze. Aligning that ring with the contact point of your racquet should give you slightly better response, although it might lead to shorter ball life since you'll always be compressing the ball right along a seam. So I marked the seams on the balls which did have "strong seams" before proceeding so I'd know how to align the drill holes.
2. Next I drilled a 5/16" hole in the top above the logo, and two 1/8" holes an inch apart on the bottom below the logo. The top hole turned out to be far wider than necessary. A 3/16 or 7/32" drill hole turned out to be plenty; it only needs to be wide enough to allow a double-width of the loop rope to fit through, and the same size hole works for all three holes.
3. The photo at right shows three finished balls, all of which have had at least an hour or two of actual play. So I assure you this works. Note the width of the two bottom holes...too close together, and the force of a hard shot could start a split in the core rubber. I'm not sure if there are any drawbacks from holes drilled too far apart, though, so always err on the side of too-far-apart.
4. The loop rope is just leftover running-shoe lace. The same rope used for the tether pole can also be used here, though...I just happened to have some spare lace.
5. The hard part is threading a double width of the rope through the bottom holes, which you have to do to produce the "cradle" effect on the bottom of the ball. You really need to pull like hell to get it through unless you've drilled very wide holes. (And keep in mind that the wider the hole in the ball, the greater the effect of that hole on the structural integrity of the entire ball...smaller is definitely better.) The top hole will need to be wide enough for a triple thickness when it comes time to thread through the second bottom hole. I made a heavy but compact hook from some stiff, thin-ish clotheshanger wire and threaded the lace through the ball from bottom to top. Then it was a simple matter of pulling the lace through from the second of the bottom holes to complete the "cradle" effect.
6. This left me with both tips of the lace poking through the top hole. My first ball, I made simply by tying off the lace and leaving it at that. But note where I put the knots on these balls: as close to the ball as possible. Keeping the knot close to the ball reduces the wear on that knot that can occur when the racquet's rim bashes against the rope when you mis-hit a shot. I strongly recommend putting the knot in the position shown in the photos.
7. I then tied off the lace at about the 5" mark using a reef knot (a double half-hitch or combined half-hitch will also do), and clipped the leftover lace off the knot, leaving me with a tennis ball with a 5" loop tether, just enough to allow me to fit the entire ball through the loop with a little bit to spare. If the ball won't fit through the loop, it won't properly tie itself to the loop on the pole tether.
8. Finally, I used a lighter to melt the knot until it stopped shrinking from the heat. This insures that the end of the knot is solid, tough plastic that can't be pulled apart from strain. The balls you see here have taken the hardest hits I could throw at them. None of them show the slightest sign so far of any meaningful damage or wear.

Attaching two loops to each other isn't always as intuitive as some of us might think, so here's how it works. To attach the ball to the tether, first insert the loop on the ball through the loop on the end of the tether (top left). Now pull the loop on the ball back over the ball (top right). This is why your ball's loop should always be large enough to fit the ball through; the loop on the tether should be as small as is practical (mine's too large) to reduce wind resistance. Once the ball's loop is pulled back around the ball, the two loops are firmly connected to one another (bottom left). Pull the ball, not the loop, to tighten the connection evenly for both sides of the loop. When you use synthetic rope, this "knot" can easily be pulled apart using your fingernails.

Finally, here's a few tips I picked up in the process that might help when you make your own balls:

• It takes about twenty minutes to make your first tethered ball. (Figure in the learning process involved!) It takes half as long for each additional ball that you make in the same session. I made up six in a little over an hour.
• The lighter the lace, the better, as long as it's true synthetic lace, since you want as much strength but as little wind resistance from the lace as possible.
• Dollar-store "floor protector" tennis balls might feel very stiff to the touchm but they have almost no bounce. Do not use them.
• Do not use "kid" balls; they are made with significantly less bounce than adult balls. Adult practice balls tend to have more bounce, and you need all the response you can get for tethered tennis.
• Do use name-brand practice balls. If it comes in a bag, not a can, and feels as stiff when new as balls that come in cans, then you've got a good ball for tethering.

And that's about all that I can tell you at this point. I absolutely love my tall pole...I live in a swampy area, so insects keep me away from my pole through most of June and July, but the only thing that keeps me from getting out and venting the frustrations of the day on a tennis ball for an hour or so in the evening for the rest of the year is a hyperextended elbow...and that's something that I'd better add a word about.

Hyperextension injuries

I played tennis every day in my teens. I didn't play at all for nearly 30 years until I put this pole up, and I quickly discovered something that I should probably mention in some depth here.

What I love most about this idea is that it forces me to exercise my backhand as much as my forehand. In fact, I have to exercise both equally to use it. But that's a problem if, like me, you were trained "classically" to hit one-handed backhands.

It's less of an issue when you're young and strong, but as we age, we tend to overextend our muscles, and we don't recover as well from surprises...like whiffing a backhand. Hitting a solid one-handed backhand is one of the most satisfying feelings you can have in tennis. Whiffing one is one of the most painful. You expect the resistance of the ball and instead swing through air, stretching your elbow beyond "flat" into areas that it shouldn't go...and it hurts like hell and takes weeks to heal.

If you don't make a conscious effort to always hit two-fisted backhands, you may hyperextend your elbow, and if you do, you need to stop playing immediately unless you're certain that you can make yourself hit only two-handed backhands for the rest of your session. A second hyperextension could cause ligament damage that might only be repairable with surgery...if it's repairable at all. It's a serious issue for older players.

The best protection against hyperextension is to train exclusively using two-handed backhands. It's a better workout, actually - a two-fisted grip forces you to travel to your shot more than a one-handed grip - but admittedly it's a tough habit to learn if you were browbeaten into the perfect 135-degree wrist angle by an overbearing youth tennis instructor...or, like me, the arm attached to your top hand on the backhand happens to be a couple of inches shorter than your bottom hand.

Update 08/11: P. Parsons writes: "The problems you report with hyperextension are usually caused by bad technique. Either the grip is wrong or the backswing is wrong. A proper backhand shot should never cause a hyperextension just from catching air." P. is absolutely right. So unless you've had your swing evaluated by a pro or a knowledgeable amateur, assume that your technique is bad. It's always better to err on the side of safety...unless, of course, you're trying to impress a woman.

Repetitive strain injuries

This is another risk of this particular form of recreational exercise. Fortunately, this risk is almost entirely avoidable.

When I last played tennis, RSI's were something you had to put up with to play tennis, not something you had to put up with to have your own website. Then, in that magical summer of 1975, everything changed. A black man was ranked second in the world, and he worked with Head's tennis division to produce the first consumer tennis racquet made from composite materials: the Head Arthur Ashe Competition. It was also one of the most expensive ever made. I actually spent an entire week's pay that summer - $125 - to buy one of these racquets; I was that deeply into tennis. And it was people like me who allowed Head to accumulate enough working capital and consumer awareness to buy the Prince company, which had just begun producing the world's first large-head tennis racquet, and begin offering the oversized-head racquet at affordable prices. I chose the Ashe Competition over the Prince that summer partly because the Prince was still considered a bit fruity for men's play and partly because it cost closer to $175. But within a year, my Ashe Competition - and every other wood-construction racquet on the market - was permanently obsolete. Gee, thanks, Head...we're all eternally grateful.

Before the large-faced racquet, mis-hit shots sent nasty vibrations through the racquet and up your arm; you could literally experience a feeling close to that of sticking a fork into an electrical socket if you mis-hit badly enough. Large-faced racquets not only disperse this vibration more effectively, they reduce the transmission of vibration even from good shots. And the newer racquets do it even better.

So is the message clear? If you're installing one of these for some enjoyable fitness activity, don't sabotage yourself by using old racquets, no matter how good they were "back in the day". I recently purchased a new Head racquet at one-third the price of my old Arthur Ashe which doesn't just have three times the sweet spot, but it damps vibration so effectively that I haven't had so much as a twinge since starting to use it.

Truth to tell, I actually found a near-new Ashe Competition racquet at a local thrift shop a couple of years ago, and I used this with my tetherpole for nearly a month before getting the new Head. I developed pain in my forearm and suffered exaggerated discomfort from a typing injury I picked up fifteen years ago. Since using the new racquet, all of those symptoms have disappeared.

I also use a padded Pilates glove when hitting the ball around, and that seems to reduce the sense of discomfort even more on those occasions when I mis-hit a shot so badly that I can feel it.

I can't stress too highly how worthwhile it can be to upgrade your equipment if you're still using old tennis or racquetball gear. The newer equipment really is a dramatic improvement over the old, and it's better for your health, too.

Two-player use won't be very practical for many people. In the first place, you can't really put this type of pole on a lawn unless you enforce a rule that no one plays in shoes that can chew up grass. So it's best placed at the end of a driveway, or in some location that allows you to use it while standing on a paved, gravel or stone-tile surface.

You can play competitively with another person using tennis balls instead of a tetherball, but classic tetherball isn't practical with the smaller ball. I've invented my own version of "tether-nis" for two players in case someone wants to play me at some point, and it works something like this.

In classic tetherball, a point is made when one player wraps the ball rope completely around the tetherpole to the point where the ball touches the pole, and a game is typically won at ten, fifteen or 25 points. In my version of "tether-nis", you can serve to either your forehand or your backhand, and a point is made each time a player hits the ball twice in a row without the other party touching it. Any touch or deflection counts, even if it doesn't make the ball go in the opposite direction. Play continues until the ball hits the pole or comes to a rest, so a player could make 20 points on a single rally by hitting the ball backhand-then-forehand and not allowing the other player to touch it. I recommend a game total of 50 points, but playing to 10 could work too if you choose to play in "sets" (e.g. you need to win 3 games before your competitor in order to win a set). There are subtleties that will need to be sorted out to make this type of game work for two people, but I'll leave the details to you.

One of the problems of two-player "tether-nis" is that it can be a bit like pool: if you run into a good player, you might never touch the ball. I've had runs of 20, 30, even 40 strokes in a row which I knew a competitor would never be able to reach, and I'm just a hacker.

Click the pic to view a larger image of my sketch sheet. I tried to represent as much as possible of the construction and use of the device, keeping in mind that this might be most useful and most wanted in non-English or multilingual neighborhoods.

If anyone is interested, I have a design for a virtually indestructible mechanism which will allow tether poles to be installed for inner-city use. The mechanism can be built into a 12-to-14-foot length of discarded steel pipe, or built separately as an attachment to a fence rail or utility pole installed for community recreation. As with hoops, users will have to supply their own balls; a URL on the side of the pole (or simple visual instructions stencil-painted to the pole) can tell the user where to get information on how to quickly create their own tetherball or tether-tennis cord for use with this mechanism. The user-supplied cords needed for inner-city tethersports require nothing more than the same cord and ball which I describe here, or a purpose-built tetherball and tether rope. The mechanism exists to allow this tether to be attached temporarily to the top of the pole and instantly removed with the pull of a lever or press of a pedal when play is over.

Best of all, no new hardware, other than three heavy nut/bolt sets, are required. All of the pieces needed to make this device are easily found in any big-city scrapyard, and could probably be had on request as donated goods. The device can be constructed using relatively common tools with about twenty minutes of cutting and machining and a couple of minutes' welding, and once assembled can be installed on a steel or wooden pole in less than a half-hour by any competent handyman or maintenance person. It should have a maintenance-free service life of at least several years, should prove very difficult for vandals to damage, and poses no more threat in a community than a basketball hoop.

It's easy for actual users, too. All you need is a tethered tennis ball similar to those shown above, a 30-foot length of ordinary rope for setting up your tether, and a 15-foot tethered ball with a rag tied to the far end.

Click the "thumbnail" at right to load the full-size sketch sheet (163kb). It should contain all the information you'll need. These sketches, professionally-redrawn and stenciled onto the pole itself, should provide all the information anyone would need to understand and use the toy. This design is the intellectual property of the author, and its incept date is verifiable via Internet archives and search engines. This design can be used without permission for private one-off manufacture or not-for-profit applications only.