The client asked and the trainer- who studied Physiology - answered A GOOD WORKOUT DESERVES A GOOD RECOVERY ... Says Margo - Your trainer Contrary to popular opinion, lactate or, as it is often called, lactic acidbuildup isnotresponsible for the muscle soreness felt in the days followingstrenuous exercise.(1) The muscle soreness aka DOMS or Delayed Muscle Soreness is a result of “damage” on a cellular level that is physical , much like shredded velcro. Muscles actually produce force using a catch and release method like real velcro and it puts a strain on the entire connection from bone covered tendon to the belly of the muscle (widest part) to the other attachment of muscle to bone. The force needs energy. You burn calories to produce this force and even use up more calories repairing the muscle system post workout. You can roughly measure the shape you are in by when the onset of soreness starts. ONSET OF SORENESS