The Gymnic web site doesn’t say anything about their balls being burst-resistant. All I could find was:

The Gymnic Ball Line is known throughout the world for its exceptional quality and durability.

and

The manufacturer is not liable for any damage caused by wrong ball usage.

It is also says on the web site not to inflate with an air compressor. Why? Probably because an air compressor can result in over-inflation and the ball is NOT burst-resistant!

I have been thinking about this Cisco thing, and obviously it is very unfortunate and devastating for Cisco. It certainly hurts the team and fans. But I am starting to conclude that some of the blame has to fall to the user, and the Kings training staff.

Let’s be generous and suppose ball takes up 750 pounds of weight. Cisco weighs around 200, and he has a total of 180 pounds of weight in his hands. So you say, well, he is well within the limits and should be OK? Not necessarily.

Simple physics tells us that F = M*A : Force = Mass x Acceleration. Is a ball more likely to burst is you are lying flat and still with said dumbbells, or if you are bouncing up and down (acceleration) on the ball? Obviously the latter.

I am not saying he was bouncing, I wasn't there, but if the user is shifting his weight, getting into proper position with weights that heavy, he is adding to the force put onto the ball. Done repeatedly the material will stretch until there is no more give.

These exercise balls are designed for CORE (abs, lower back, hip flexor area) work. Your core muscles flex to keep your body stable throughout the exercises. But 90 lbs. of dumbbell in each hand is too much weight! Common sense, and safety precautions would dictate that. Core work is done with no weights, or lighter weights starting at 5 lbs, up to 30 to 40 pounds max, even for real fit, strong athletes.

I have spent a lot of time in the gym, and I have never seen a guy with dumbbells that heavy combined with an exercise ball. He was doing a chest exercise. The abdominal muscles acts as stabilizers and contract isometrically when lying on a regular bench to support this movement. There was really NO reason to be lying on a ball!

(Not to get too technical, but I think he would have been better off doing chest flys with a lesser weight than chest presses.  The range of motion forces the core muscles to work more.) 

Assigning blame at this point is irrelevant at this point as it effects the team.  Cisco is sidelined at least four months, he will be sorely missed, and that is that.  And certainly I don't want to kick a guy when he is down.  I do think it is interesting to speculate from a liability perspective, though.  Who is more at fault, the user or the manufacturer? Was there negligence on the part of the user, or was the ball poorly constructed with inadequate warnings?  Questions best left for judges to answer, I suppose.  I will be shocked if the Kings do not pursue legal action in the very near future.