John, Instead of life cycles, what you really should be talking about is fatigue. What little I can remember, fatigue failure is dependant on load. Some lighter skiers will be able to get 10 years out of a ski and some brute skiers will go through a couple skis a season. I've been out of the classroom too long to quote test procedures and formulas so someone that has an background in mechanics and materials will have to chime in with the proper way to run a test on these skis. If you want to run a fatigue test on a ski, I'm thinking you will need to run it at various load levels. For a skier to use the information from the test, they will need to know how much load they typically put on the ski. Sounds like a good project for an engineering student working on his masters. Dave