Okay so everytime I ski my quads and calves give out on me. I have been going to the YMCA and although I am making progress it was not enough. Soooo, I tried a new approach. KID BASED EXERCISE. I put my son on my back in piggyback style and do calf raises on a step, he weighs 103 pounds. I then put my daughter on my back and do squats, she weighs 73 punds. This sounds crazy but it works. My last ski trip I lasted all day. If your legs are weak use your kids.