Has anyone ever analyzed how poor or unefficient technique has been a hinderance to their endurance? Any success stories about improving technique (becoming more efficient) which led to better endurance ie not getting tired as quickly. I suspect I'm using way to much energy in an inefficient manner and it tiring me out, like a boxer throwing too many lame punches.... I think Federer must have perfect technique as he never seems to get tired. He even said in his match against Ferrer of all people- "I wasn't tired and I can tell he was".