String Theory – A Simple Guide to Tennis Racket String Tension

String tension is the single most important factor affecting the playability of your tennis racket.

You could trawl the earth (and web) for the perfect frame, grip, head size and appropriate celebrity endorsement, but if you string the racket at the wrong tension it will all be for nothing.

What is string tension?

Put very simply, tension refers to how loosely or tightly the strings are secured to the frame of the racket. It’s expressed as a measure of pounds or kilograms (depending on where you are in the world) which indicates how firmly the strings are pulled taut by the stringing machine.

Typically the recommended tennis racket string tension ranges between 40 and 65 lbs, that’s 18.1 to 29.5 kg. However most tennis rackets these days come with a unique tension range as specified by the manufacturer.

You can usually check this out online or by looking at the information printed on the inside of the frame or the racket’s throat.

Those figures will have been lab tested so it’s best not to ignore them. In fact, if you string your racket tighter than the upper range there’s a risk of damaging – even cracking – the frame.

Benefits of lower tension strings

Given that a typical recommended range is between 40 and 65 lbs, stringing a frame at anything between 40 and 50 lbs would be considered low tension.

There are three very clear benefits to hitting with lower tension strings – power, comfort and feel.

Power is the most obvious. A looser fitting string provides far greater elasticity or ‘trampoline effect’. This means that when the ball hits the racket it produces more spring, propelling the ball with greater force.

It also increases what’s known as ‘dwell time’ – the amount of time the ball remains in touch with the strings.

Now, there is some debate over how much difference this makes to a racket’s performance. But certain players – this writer included – will tell you that it just improves the overall ‘feel’ of the racket.

Finally, what a low tension string offers is more comfort. The looser strings absorb much of the shock when the racket hits the ball which makes it easier on the joints. Lateral epicondylitis – more commonly known as tennis elbow – is caused by repeated jarring of the arm while hitting. But that effect can be relieved by lowering a racket’s tension thus easing the load on the joints.

Benefits of higher tension strings

Any racket strung between 55 and 65 lbs would be considered high tension. And while you’d be sacrificing something in terms of power and comfort there is one clear advantage – control.

In contrast to a lower tension racket, the ‘trampoline effect’ is much reduced which although means a reduction in power, also means a reduction in variability as the ball ricochets off the string bed.

Think of it this way – if you throw a ball at your bedroom wall you can confidently predict the angle it’s going to bounce back at. Throw it at your saggy old mattress with the worn out springs? It’s anyone’s guess.

Most professionals opt for a higher string tension as they’re well capable of generating their own power. But they thrive on the greater consistency and precision that the higher tension offers.

Do lower tension strings offer greater spin?

Looking around the web we see a lot of sites claiming that stringing your racket at lower tensions will improve your spin game. There are even a few claiming the exact opposite! But here at Heavy Topspin we think that’s…well a lot of spin.

According to this study published by Sheffield Hallam University’s Sports Science department, string tension does not affect spin at all.

Higher tension rackets do offer greater control but – as noted above – that control does not come from spin, rather a more consistent responsiveness.

To put this another way, Roger Federer was known to string his rackets at a very high 59.5 lbs during the hard court season. But he still managed to generate a pretty handy amount of topspin (2200 rpm on his backhand). 

The Fed – Highly Strung

Do higher tension strings last longer?

Again, lots of sites seem to think that strings fitted at a lower tension are less durable. The claim is that because they have a tendency to move around and rub against each other they wear out more easily.

In our experience that’s not the case and if there is any difference it’s negligible. Counter that with the fact that higher tension strings have a tendency to snap more easily and it probably cancels out any advantage anyway.

Our advice – don’t let durability be a factor when deciding string tension.

What is the best racket string tension for me?

As with choosing the right tennis racket, selecting the correct string tension comes down to many factors – your style of play, level of experience, which string type you go for and of course personal preference.

If you’re brand new to the game, a good starting point is the middle of the recommended range of your particular racket. As noted above you’ll find that printed on the inside of the frame or occasionally on the throat.

So on a racket with a range of 40-60 lbs you might start at 50 lbs.

From there it pays to experiment.

If you’re a beginner, lack a lot of natural strength or are just looking to rinse some more power from your racket you could try for a reduction in tension. But be careful! You might find it much harder to control your shots.

Very small alterations in tension can make a large difference to performance so our advice would be to adjust in small increments.

If, when playing in the middle of the tension range, you do find your shots are hard to control you might try upping the tension slightly.

HT Tip - If you are aiming for greater power it might be worth working on your strength and your swing before opting for the easy fix of reducing tension. This way your accuracy and control doesn’t need to suffer and your overall game will improve.

Should I adjust string tension depending on which string type I use?

The type of string that you choose will have an effect on which string tension to select.

Natural gut, multifilament or nylon strings tend to be fairly flexible and elastic so you probably won’t need to adjust for these. Although if you are changing from a naturally stiffer string you may want to go one or two pounds higher than the tension you’re used to.

Polyester strings on the other hand are much stiffer so would require going the other way. Find the middle of the racket’s recommended tension range and then drop it by a couple of pounds.

Should I carry multiple rackets at different string tensions?

If you’re a more advanced player competing at club or tournament level, chances are you’ll carry more than one frame onto court.

Not only will this prevent you from forfeiting if you break a string, it gives you the opportunity to adjust your string tension depending on match conditions.

In fact, most professionals carry between six and ten rackets for this very reason.

But which factors could influence your choice of string tension?

Climate

Weather can have quite an impact on the speed of a match or the flight of a ball.

On very hot days the ball tends to fly a little faster so you may be tempted to switch rackets to a higher tension string.

Conversely on days with a lot of humidity or on a wet court the ball retains some of that moisture, slowing play down. In that case you could opt for a lower tension string to compensate.

It’s hard to predict exactly what kind of conditions you’ll be facing in advance of a match so it can be useful to make the switch once you’re on court.

Altitude

Altitude is a little easier to predict than the weather. But if you’re a touring pro or just travelling somewhere new, you could find yourself playing conditions you’re unused to.

At higher elevations the air is a little thinner meaning the ball flies faster. If that’s something you’ve never experienced you could find your shots landing long more often than not. But if you carry a higher tension racket it’s pretty easy to make the switch.

Court Surface

As we explored in our piece on the fastest court surfaces, typically clay courts are much slower than grass for example.

Many pros will have their rackets strung a little looser during clay court season to give them the extra power the surface demands.

How long will my racket retain its tension?

Rackets lose tension over time.

In fact the biggest drop off is in the 24 hours after stringing. It’s said most rackets will lose around 5-10% of tension even without a ball being struck.

That’s worth being aware of, as if you do practice immediately after stringing you won’t get a realistic idea of how the racket’s going to play. This is the reason that professionals ensure their frames are strung at specific times before every match.

Pros have their rackets strung at various tensions depending on conditions

After those first 24 hours the racket will continue to lose tension but at a much slower rate. There’s no hard and fast rule for when a racket needs to be restrung – it depends on all sorts of factors. But a general rule is to base it on how many times you play a week. Once a week? Restring once a year. Three times a week? Restring three times in a year.

Saying that, if you notice the performance of your racket has dropped off there’s no need to wait. Nobody knows your game better than you.

Tension Headaches?

Hopefully we’ve helped clear up any string tension confusion. But if you have any comments or questions don’t forget to drop us a line. And if you’re looking for a new racket entirely, be sure to check out our helpful guide.

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