Tennis Elbow: Is the Culprit the Strings or the Racket?

After reading comments on how poly strings would cause tennis elbow or how an overly stiff racket causes discomfort, my curiousity is piqued. Does the string matter more or the racket?

I have always played with stiff rackets with RA at 70+ and with multifilament strings strung close to 70 lbs. I cannot recall one single incident of wrist, elbow or shoulder pain. While I have occasionally experienced some discomfort or soreness after a long layoff, there is no injury that I can recall. Not once. So I cannot associate tennis injuries with a stiff racket.

I have also tried using my friends' stiff rackets strung tightly with a full bed of very stiff kevlar strings. I lasted less than 5 hits with the ball before concluding that I cannot handle it. My recollection of a stiff racket with stiff kevlar strings is extremely uncomfortable, even painful.

When I tried tightly strung stiff strings on a very flexible racket (RA 50+), the jarring discomfort and pain still shot up my wrist and elbow with every impact.

So my naive conclusion based on my limited experience is:
--> stiff racket + soft strings = no arm pain
--> stiff racket + stiff strings = arm suicide
--> flexible racket + stiff strings = arm suicide

For now, the bigger culprit seems to be the strings. But then, I also know some people who enjoy kevlar or poly strings done at 60+ lbs! And they are STILL injury free after many years!

Finally, it dawned on me, that the chief culprit for almost all wrist, elbow and shoulder injuries is OFF-CENTER CONTACT!

When impact is at or very near sweetspot, there is no vibration. No jerk. No jarring feeling. The sweetspot is where the centre of gravity (CG) of the racket frame is. Since it is the most stable part of the frame, why would there be vibrations?

If I draw from the experience of Sean Fister, who is a Three-time World Long Drive Champion, you should feel absolutely nothing when impact is right smack in the middle of the sweetspot. (link) This probably explains why Nadal can string a full bed of poly at 55 lbs and still hit so well. (link)

The other important reason, I believe, can be attributed to the swing mechanics. A player who grips the racket tightly and "muscles" the ball will receive a lot more vibrations than someone who grips lightly and swings the racket forward like a pendulum.

Most of the pros start their swing "bottom-up". After they shuffle their feet into position, a right-handed pro always shift his body weight to the left first, then turn his shoulders before his hand swing the racket forward. Power is generated from the hips and body and the racket is swung, not muscled through.

So, to prevent injury:
1. always try to get the sweetspot
2. swing the racket with a light grip

A good "insurance" would be to use low tension, soft strings or an arm friendly racket if our sweetspot hit percentage is low.

Generally, my other experiences are:
- players with wrist problems seem to do better with head light rackets strung with soft strings at low tension
- players with tennis elbow do better with heavier rackets that are overall still head light
- players with shoulder problems do better with lighter racket