After exercise the muscles always hurt – this happens for two reasons:- production of lactic acid;- damage of muscle tissue. Lactic acid appears in the tissues during physical activity – active muscle activity requires a large amount of oxygen to oxidize glucose to carbon dioxide). As a result of insufficient supply of oxygen, glucose is oxidized not completely, but only to lactic acid. Acid tends to accumulate in muscle tissue, it is not time to output due to high-intensity anaerobic exercise, therefore, irritates the nerve endings causing pain. These feelings often arise when you do crunches rapidly, especially in the latter movements, when you need to work in full force.The second reason for muscle pain after workout – micro-cracks or damage some of the components of muscle tissue. This pain usually occurs the next day after a workout – before you are well trained, and if classes were held after a long time break or you are just starting your regular workout, the muscle pain is inevitable. Microtrauma of the muscle fibers are not dangerous, the tissues is gradually restored and the muscles increase in volume – then there are specific blocks of the abdominal press.The most dangerous type of pain you can experience in the field of press, it's throbbing pain. If the press began to ache sharply, the pain sharp and shooting, it is likely that injury. Often painful feeling in the abdomen accompanied by the appearance of hematomas and bruises – you should remember the moment when I got injured. A situation when the press hurts all the time, frequent, if, after receiving microtraumas you are given the opportunity to recover fiber and continued to train, increasing the load. Nasty pain that require urgent treatment to the doctor – hernial protrusion. Painful sensations arise when hernia incarceration, as the front wall of the abdomen is weakened, and the increase in pressure inside the abdomen causes a prolapse and incarceration of internal organs. In this case, you should consult a doctor as soon as possible to prevent tissue death.