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So I was looking at the work= force x distance equation and was just wondering if for example I normally do 100 dead lifts at 100 pounds. Would I get the same calories burned if I did 50 dead lifts at 200 pounds. According to the work formula I am doing the same amount of work. If this is true how do you know our muscles use the same energy at double the weight and half the reps? How can we prove that our muscles are burning the same energy with half the reps at double the weight. Do we just accept it because it satisfies the work formula?