Badminton players have been known to argue endlessly over the relative merits of one racket versus another, and to agonize for months before deciding which one to buy. But before you plunk down as much as $100 on a new racket, think about this: You don't hit the shuttlecock with the racket. You hit it with the string! By changing how your current racket is strung, you may be able to improve not only its performance, but your own as well.

The most important variable in badminton string is its gauge, also known as diameter or thickness. Tournament players may boast about using super-responsive 22-gauge string, but what does that mean, and how does string gauge affect play?

String gauge is designated numerically, with thicker strings having lower numbers, as shown in the table:

Gauge Diameter 20 .80-.90mm 20 micro .78-.82mm 21 .70-.80mm 21 micro .68-.72mm 22 .60-.70mm

The gauge designations were originally based on standard industrial wire gauge sizes, but as manufacturers began developing racket string in a variety of different sizes, the industry agreed that the numbers would represent a range of allowable diameters, rather than a single, exact size. All consumer string packaging indicates the size at least as a gauge designation: some packages include the diameter in millimeters as well.

The "micro" designation is a recent innovation. Note how some of the gauge size ranges overlap one another. A string with a diameter of .71 mm may be called a 21 gauge by one manufacturer, while another may label it as 21 micro. The only difference is a question of marketing.

String thickness can be measured with a wire gauge or a micrometer, but make sure you do it with the string off the racket, under no tension - in other words, before the racket is strung. Thickness decreases when a string is stretched at 15 lb. to 25 lb. of tension, and a reading taken under those conditions can be misleading.

As you would suspect, thick and thin strings perform differently in the racket. No one size is best for all players. Different playing styles (and budgets) lead players to choose different combinations of characteristics. We'll take up just one of the properties here - that of durability.
Thick string lasts longer than thin string. Assuming that two strings are made of the same materials, and use the same construction, the thinner one will break more easily. Simple, huh? This doesn't necessarily apply if you're comparing a thin, premium-quality string with a thick junk string, but as a rule of thumb, it's pretty reliable. Extra-thin, 22-gauge strings have some advantages, but durability isn't one of them: you have to be willing to replace broken strings more often if you use this ultra-thin gauge. On the other hand, a heavier, 20-gauge string could last you through an entire season.

There are two main causes of string breakage. The first is notching. As you hit the shuttlecock, the cross strings (or "crosses" - the shorter, "horizontal" ones) are pounded against the main strings (or "mains" - the longer, "vertical" ones) several hundred times in the course of a match. The crosses slowly cut notches into the mains, and eventually they cut right through. Obviously, a thicker string will stand up to deeper notching before it breaks. By the way, it's almost always the mains that break first.

The second major cause of breakage is over-stretching, which can occur during a particularly hard or off-center shot. This is especially so if you hit the shuttlecock near the head of the frame instead of in the sweet spot. The string wants to stretch equally on both sides of the
shuttlecock, and on a mis-hit, there's not much string to work with on one side: it tries to stretch too much, and it breaks.

So, is a thicker string necessarily preferable? Of course not. Durability is just one desirable characteristic. Thinner strings, for example, give a player more power, which is why 21microgauge is "hot" among top players. There's also cost, control, "feel," ease of stringing, and a few others properties to consider and balance against one another when you're replacing your strings. If I had just one word of advice to give, it would be this: if the string in your racket is old, replace it now. Your game could see an immediate improvement.

 Source : USA Badminton