The Importance of Elongation Percentage

While I was working on this post, it amazed me to see Tim resurrect his earlier writings on the causes of tennis elbow and, right there, one of the major problems surfaced: avoiding strings with too little elongation.

Unfortunately, string companies don’t publish information like this on their products and, with the popularity of polyester strings (of which very few have much elongation at all), the emphasis has turned to stiffness, not elongation. Stiffness is, I think, not the best indicator of string comfort; elongation percentage is a much better source of information.

What is Elongation Percentage?

Simply put, elongation percentage is how much an item stretches under tension, measuring how “ductile” (able to remain pliable) it is. A higher-elongation string can dissipate energy (stress) better than one that stretches less, which should make it more comfortable during play, while also putting that energy back into the ball for increased power potential.

How do You Test for Elongation Percentage?

While we don’t have reliable sources for the elongation percentages of most strings, it’s quite easy to do a rudimentary test in the field. Historically, we have tested elongation percentage at 60# tension, and that is the tension that I have tested at over the years.

My procedure is, while not necessarily what manufacturers do, quite simple: I clamp a length of string in the machine, measure it (in millimeters), apply 60# tension, measure it again, and take the percentage increase in length as the elongation percentage of that particular string.

I’ve included elongation percentage measurements for several strings below, and will update them as often as I can. If you have a string you are curious about, let me know and I will get to them when I can.

How Does Elongation Percentage Help Us as Tennis Players?

For most tennis players, the comfort and power levels of a string are much more important than spin potential (since most players don’t hit a lot of spin) or durability (since a lot of them don’t break strings before their useful life is over). It is incumbent upon us, their racquet technicians, to know which attributes are most helpful to them and educate them about it. Elongation percentage is, in my opinion, at the top of the list.

 

Brand	Model	Gauge	Color	Type	Elongation % @ 60#
Alpha	Gut 2000	17	Natural	Multi Nylon	21.1
	Prodigy	16	Red	Multi Nylon	15.32
	Viper MXT	17	Gold	Solid Core SG	5.36
Ashaway	Dynamite	17	Green	Multi ZYEX	13.79
Babolat	Addiction	16	Natural	Multi Nylon	11.35
	Pro Hurricane Tour	16	Yellow	Mono Polyester	5.03
BDE	Rallye	16	Natural	Natural Gut	10
Bow Brand	Championship	16	Natural	Natural Gut	9.85
Clarke	Nylon	15L	Natural	Solid Core SG	12.5
Dunlop	Explosive Red	16	Red	Mono Polyester	9.7
	Synthetic Gut	16	Natural	Solid Core SG	12.9
Forten	Sweet 16	16	Natural	Solid Core SG	9.6
Gamma	Live Wire XP	17	Natural	Multi Nylon w/ZYEX	8.97
	TNT2	16	Natural	Solid Core SG	13.59
Gosen	OG-Sheep Micro	16	White	Solid Core SG	10
	Polylon Comfort	17	White	Mono Polyester	5.4
Head	IntelliTour	16/17	Gold	Polyolefin Ribbons	19.2/12.8
Kirschbaum	Super Smash Spiky	16L	Gold	Mono Polyester	6
	Touch Multifiber	16L	Gold	Multi Nylon	13
Luxilon	ALU Power	16L	Silver	Mono Polyester	6.67
	Big Banger Original	16	Beige	Mono Polyester	4
	TiMo	17L	Silver	Mono Polyester	7.5
Prince	Lightning XX	16	Clear/Silver	Solid Core SG w/foils	15.04
	Synthetic Gut Original	16	Gold	Solid Core SG	8.96
Pro Supex	Premier Ace	16L	Orange	Mono Polyester	3.7
Signum Pro	Poly Plasma	18	Orange	Mono Polyester	4.04
Tecnifbre	NRG2	16	Natural	Multi Nylon w/PU	8.3
	X-One Biphase	16	Natural	Multi Nylon w/PU	8.72
Topspin	Cyber Flash	16	Silver	Mono Polyester	3.47
	Poly Power Soft	16	White	Mono Polyester	3.68
Wilson	Natural Gut	16	Natural	Natural Gut	8.97
	NXT	16	Natural	Multi Nylon	7.9
Yonex	Tour Super 850	16	White	Multi Nylon	12.4