We all know that sound. That dreaded ping sound just as you’ve hit (or mishit) the shuttle. There’s that moment when you look at your racket knowing the string has gone. Then you show it to your opponent with a puppy dog face and they look back with understanding and empathy. String tension in badminton is often misunderstood so I hope this article helps to improve your knowledge on the right string tension for you.
Breaking strings is one of the situations we must accept as inevitable as badminton players. Whether it’s the natural degrading of the strings or an unintentional mishit, it’s an annoying situation. Particularly if it means a point was lost.
Getting a racket restrung might be confusing if you’re new to the sport. You have two decisions you have to make, the type of string and string tension. This article will focus on string tension.
The Spectrum of String Tension
Most factory-strung rackets come strung at about 18lbs – 20lbs. At the high end, some professional players have their rackets strung in excess of 30lbs. For the majority of players, between 20lbs and 30lbs is normal between a range of beginners to advanced players, including some professionals. A mistake is to assume that the professionals play at a higher string tension, therefore, it must be the better option. In order to understand why they play at such high tension, we must first understand the relationships between tension and performance.
The Sweet Spot
The most important thing to mention when discussing tension is the sweet spot of the racket. The sweet spot is the area of the string bed where the shuttle should be struck. At this point, the strings transfer the most energy from your shot into the shuttle. This is because the strings flex equally at this area of impact. As the string tension increases, the sweet spot gets smaller. This is important to remember.
The image below shows the sweet spot of a low-tension racket (red) and a higher-tension racket (Blue).
When you mishit the shuttle you are causing an uneven distribution of energy on the string bed. When you hit the sweet spot the energy of the shot is spread evenly. By nature, the strings are the tightest around the frame of the racket. It is more common to snap strings prematurely at these points. At higher tensions, the strings are extremely tight in these areas. When a mishit occurs the strings do not flex as much and do not absorb the energy in the same way looser strings might. This force causes the string to break.
At low tensions, the sweet spot of the racket is larger. There is less chance of mishitting the shuttle. In the event this does occur, strings are more forgiving as the energy from your shot is more easily absorbed. The strings have a little more give and flex to take the impact.
Take a look at the video below to see how many times racket strings can snap in a professional match. Taufik Hidayat played with at least 30lbs of tension. They will be extremely consistent in hitting the sweet spot of the racket on every shot. If you are not playing at this level, you probably don’t need your strings strung this tightly. The average player does not have the same consistency and would be snapping strings left, right and centre.
Power
It must be emphasized power is generated by having good technique, strength, speed and a number of other factors. One cannot significantly improve their hitting power simply through string tension in badminton.
Often there is an accepted truth in badminton circles that lower string tension creates more power than higher tensions. I would argue that tighter strings can create more power BUT this is totally dependent on the ability of the individual.
A beginner would not be able to hit a more powerful smash simply because they have tighter strings. But they may be able to produce more power with lower string tension. However, a professional player would be able to generate more power from a tighter string than a looser one.
This sounds slightly confusing but it all has to do with the player’s ability to distort the strings and create a rebound effect. When the shuttle hits the strings, the strings bend and snap back into position. This action propels the shuttle forward, adding to the momentum of the shot. A tighter string will rebound faster and harder than a looser one.
Badminton String Tension – Analogy For Power
A good analogy is a spring. If you had a spring and only had the strength to compress it 50% of the way down, it would rebound less powerfully than if you were strong enough to compress the spring 100%. This is the same basic principle with tighter badminton strings. They will produce more power but only if the individual has the strength and technique to distort the strings and create that additional power the higher tensions can offer. This is assuming all else being equal (same racket, same player etc).
Hooke’s Law
This follows Hooke’s Law which states that “the force needed to extend or compress a spring by some distance is proportional to that distance.” However, once an object reaches its elastic limit, this law no longer applied. Basically, until the object breaks or is stretched to such an extent that it does not return to its original shape. This uses the formula:
Fs = ke
F= Force, K= Spring Constant, e = extension
So from the formula above, the less string tension (K), the less force is required to distort or bend the strings (e). This is why lower string tensions are especially good for beginners as they do not need to provide as much force to distort the strings and therefore have more power in their shots. The higher the tension (spring constant) the more force is required to distort (extend) the strings.
Higher tension strings can store more potential energy. So if a player can distort a higher string tension racket to the same degree as a lower tension strung racket, there will be more power from the higher string tensions. Typically professional players who have excellent technique can distort higher tension strings more efficiently than the likes of us amateurs!
There is a point at which higher tensions no longer offer any additional benefit for power. The strings would effectively be inelastic and Hooke’s law would no longer apply as they cannot extend. It would be basically like playing with a wooden bat. In addition, it would put so much pressure on the frame of the racket that it would become very fragile. Any frame shot or even mishit could crumble it.
Control
The more common reason professionals have higher string tension in badminton is for control, not just power. Control is the responsiveness of the shuttle to your shot. Professional players seek an immediate response from their shots as this allows them to play shots faster and with better accuracy and feel. With high tensions, the shuttle comes off the string bed much quicker relative to lower tensions. This allows players to be more certain of their shot and play it more precisely. One way to describe this is that the shuttle sits on the string bed longer at lower tensions than higher tensions.
Shots will be more accurate because the player is able to assess the flight of the shuttle off the racket because of the higher tension as there is an immediate response of the shuttle from the racket. A lower tension would not have the same feel and the slightly longer delay in the racket coming off the shuttle will distort the player’s perception of the shot. They will also have to compensate for the rebound effect of lower string tension.
Brief Analogy on Control
If you jump in the centre of a trampoline you will bounce straight up and down. But if you jumped at the edges of the trampoline, you will find it throws you back to the opposite side. This in effect is what’s happening to the shuttle on a smaller scale.
With lower string tension in badminton, the shuttle may fly off with more angle than you anticipated if hit off centre. This is because it creates an uneven flex in the strings so will rebound the shuttle in the opposite direction it was struck. If you hit a shot off centre with a highly strung racket, the shuttle is still likely to travel to the intended destination, albeit a slightly weaker shot, or resulting in a broken string. This is what we mean when there’s a loss of control.
Injuries
Injuries from incorrect string tension in badminton are far more common among those who string rackets too tightly. These players may lack the proper technique and ability to play with such tensions. As a result, they notice that they have a lack of power in their shots. Rather than acknowledge that their stringing tension is incorrect, they try to force their shots, causing shoulder and elbow injuries. If this sounds like you, (and you’re not injured yet!), it might be time to reassess your string tension. It could take some time as it will be trial and error but your body will thank you for it!
A great article to read for further information about this can be found on Paul Stewarts Badminton Blog. A great resource of knowledge for any badminton player.
Badminton String Tension – Conclusion
String tension in badminton is a matter of personal choice but it should be governed by overall ability. Beginners and players who are less consistent should have lower tensions. This is because the sweet spot is maximised and offers a little more power. As their game improves they can slowly start increasing the tension and continue to do so until they reach a level and tension that compliment each other. Tension choice is important but power and control as mentioned above comes with practice and training. String tension is supportive of your skills, not a tool that will improve them significantly. Don’t forget to check out the two articles below for further information on badminton strings:
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Very detailed and understanding explanation! Yet I cannot watch the video which shows the video is not available. Could you please update the link or a footnote about the available zone to watch this video?
Hi Wen, thank you very much for reading my blog and taking the time to comment. I have now updated the article so that the video should be ok to watch now. Thanks for bringing it to my attention!
It’s like some boys in a gym, they always think more weight are better than the light one. However, it depends on our needs.
worth reading, explained in detail.