I def can't comment on your technique, but I find that a great way to avoid that or alleviate muscle soreness and fatigue is to stay hydrated. I found that when I ride with a camelbak and can take a drink anytime I need to my muscle-cramping and soreness both on the hill and the next day are greatly reduced. Water helps deliver oxygen to your muscles, and the burning is a build of of lactic acid. It's definitely a good idea to stay hydrated both on the hill and the day before. Snowolf posted something somewhere else about quickly switching back and forth between heel and toe to avoid muscle fatigue. I hope that helps.