Best strength results from STS (including 1 Rep Max tests) - nothing else comes close.
Best endurance/leg strength results from FIRM Standing Legs/Gin Miller's Intense Moves while preparing for backpacking trips. I could always tackle the roller-coaster trails of the Rockies. (I hate to admit it, but I think my backpacking days are behind me. Hip problems won't allow use of backpack, I fear.
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Best aesthetic results from FIRM Classics back in the day - but I had the good sense to be 26 years old at the time!
It was much simpler back then - a huge thrill every time a new FIRM was released to add into the rotation.