Q: how many calories does one push up burn

A: Not much and even doing 100s of pushups per day won't get you very far in either fat loss or muscle gain. Check out http://www.mikesfitness.com/content/how-many-calories-does-one-sit-up-burn and http://www.mikesfitness.com/content/how-many-calories-does-500-crunches-...