I'm starting to think that the power to tension equation is a parabola, not a line. The reason I believe this is if you have a high tension, no trampoline effect on the strings. If you have a very low tension the trampoline won't completely snap back, therefore less power. So now I believe that someone who wants an arm friendly string job but wants control or just poly should just string REALLY low. Please tell me your thoughts on this subject.
Best Regards,
Voltron
Hi Voltron,
Interesting idea. Here are my thoughts, since you've asked. I invite you to re-think the trampoline mental image, into that of a collision instead. Sometimes our language and mental pictures get in the way of our understanding.
1 - Consider the idea that strings dont "have power" and the string bed is not a trampoline. The USRSA has tested the effect of dropping hollow steel balls that weigh the same as tennis balls, onto stringbeds of two tensions, one at 50 lbs and one and 70 lbs. The bounce height of each was identical. Why drop steel balls? It takes ball deformation out of the equation. Why take ball deformation out of the equation? To find out what strings do without a mashing ball mucking up the analysis. This is the key distinction. It is about stringbed deformation versus ball deformation.
2 - Changing the tension of strings has been calculated to affect at most, a 1% difference in rebound speed on the court with tennis balls. Lower tensions have slightly higher bounce, or on the court, faster rebound speed because the softer stringbed deforms the ball less. The key point here is that when a ball compresses, it loses about 45% of its share of the stored impact energy due to internal friction and heat. The energy in the ball isn't really lost, it's just converted into something else which is of little use to the tennis player - heat. So power is really about compressing the ball less, conserving the enrergy loss during the collision.
3 - However, There is a point at which you can lower the tension so much that you begin to lose more energy with string deformation than you do with ball compression. That point is at somewhere in the 40 lbs of tension range.
Point: A parabola? Cool... OK - I'm with you on that but, it isn't caused by more or less "snap back" from the stringbed, or trampoline effect, as you put it. The tension to energy loss curve is about more or less deformation of the tennis ball. It's about energy conservation in colliding objects. String low for power and high for control, is an old adage, and mostly true, but going to the extreme with either idea has diminishing returns of those qualities.
Best regards to you, take care
-Jack
