Mysterious Arm Pain and Hyper Hammer 4.0 Overhaul

A playing partner asked if there could be any explanations why only a particular racket caused elbow pain when playing.

Both were strung with full synthetic gut around 55 lbs. Both specs were very close, but only the Wilson always resulted in pain after play, whereas the Head TiS6 never caused any discomfort.

Looking at the string wear in the sweetspot of the Wilson (above left picture), there was absolutely no doubt on the consistency of sweetspot impacts. So I ruled out pain due to framed shots.

Then I compared their specs:

	Wilson HyperHammer 4.0 OS	Head TiS6 OS
Weight	249 grams	252 grams
Balance	9 pts head heavy	8 pts head heavy
Swingweight	308	318
Length	27.75"	27.75"
Flex	RA 70	RA 75
Headsize	110 sq inch	115 sq inch
String Pattern	16 x 20	16 x 19

Ironically, the TiS6 was 5 points stiffer on the RA scale compared to the Hammer. So it ought to have been the more damaging stick instead!

After much probing, dry-fitting and testing, similar to what I attempted here two years ago, the culprit pointed towards two things:
(1) the very low swingweight of this Hammer, and
(2) the very extreme weight polarization (9 points head heavy)

When there was sufficient time to prepare and swing, every shot felt good for both frames, for forehands and backhands, groundstrokes and volleys. 

But when I was late, or on the run to retrieve a well-placed corner shot, the abbreviated compact swing made the racket feel very inadequate. It was powerless.

The extended length allowed me to reach the ball, but the feeble swingweight worked against me, and allowed only a very miserable pathetic tap against the full velocity of the ball. 

As a result, instead of me swinging the racket to hit the ball, it became the reverse - the ball pounding hard on the racket, which in turn twisted or deflected my wrist/arm backwards. 

With the racket weighing only a mere 250 grams to bear the impact, my arm became the shock absorber! I played with it, in stock form, for only about 10 minutes before I had to set it aside.

Literally, I had to beef up the racket by adding weight to improve its swingweight, vibration dampening and simultaneously reduce the extreme weight polarization.

The original handle was entirely hollow all the way up to the hoop. 

Most of the racket's weight was concentrated on the tip of the head, near 12 o'clock. This encouraged vibrations to travel down the hollow frame towards the handle, which was the lightest part of the racket. And then up our hand, wrist and elbow.

After stuffing one side of it, I tapped around the frame and measured the vibrations via frequency. I stopped when about 70% of the "bad vibes" were removed or reduced.

Then the old strings were cut and restrung.

A little lead was added around the grip pallet as well. And about 4 grams were added to the hoop at 4 & 8 o'clock to add about 7 swingweight points. Placing the lead any higher would worsen the weight polarization so lower was better.

Here's how it looked completed.

While some aspects, like vibrations, total weight, balance and swingweight were easily quantifiable, the most important variable - player feel/preference, remained entirely subjective.

The only way to take this further, is for my friend to make minor adjustments and fine-tune after each session of play.

Whatever the outcome, the general consensus about "light and stiff" rackets stand - that they are hazardous to our arm health.


11May2015 update:
- For those with tennis elbow or wrist injuries, just a few hits with an unfriendly frame usually flares up the pain very quickly. 
- After I handed the modified Wilson to the owner, she gave it a few air swings and proceeded to rally. I watched intently the ball impact locations on the stringbed, the amount of prep time and the magnitude of back swing.
- Added weight usually visibly slows down a player. Ironically, it enhanced this partner's swing timing. Immediately, I knew the racket had been too light earlier.
- Coupled with the extreme weight polarisation, it actually hindered her from taking a free swing as the heavy head's momentum ended up "pulling" her arm instead.
- The average pace of her shots increased. Directional control improved. 
- What she admitted readily, was the absence of any pain or discomfort. The frame felt cushioned and friendly. But she did not believe that her ball speed increased and felt heavier to me. 
- So I told her to keep this modification to herself. Then play with her usual doubles group and see what those three regular partners would say after their two hours session.
- I was updated later, that just during their warm-up rally prior to the game, her partners already remarked about her improved hitting depth, power and control. Even asking if she had been working out in the gym to achieve all that!
- Needless to say, she sent me a message, saying:
"Thanks again for resuscitating my racket... It keeps me grinning the whole day..."