Just thought I'd post a plug for this waist worn ski handle rest product that I saw in the back of WaterSki mag and took a flyer on: http://www.griprest.com/
I have benefitted from it so greatly, I'm sending the following testimonal for their use:

"Anyone who sees me buckle up for skiing for the first time always asks "what's that"? Or will later ask "how did you go hands free"? I tell them what it is, and I always say it's the best money I've ever spent. I bought it in 2007 as an aid to a weakened grip after breaking my finger in the spring. I have always worn it since. Allows me to ski much longer each time, thus has increased my enjoyment of the sport immensely. It is truly a great product. Shows no sign of wear after 3 years of use. Thanks for inventing such a great sports aid!"

A typical ski goes like this:
Wife/son hits it.
Once on plane, I Griprest until the boat's at speed, water's out of my eye's, etc.
Regrip and ski until I'm out of gas; usually the arms go first.
Griprest. My wife/son sees this and slows the boat to 25 MPH to save gas and lake.
Regrip and ski some more when the boat's back up to speed.
Repeat the above.

Anyone who wants more endurance, I'd strongly recommend this.