Glycolysis involved in glycolysis. The burning sensation in muscles during hard exercise can be attributed to the release of hydrogen ions during the shift to glucose fermentation from glucose oxidation to carbon dioxide and water, when aerobic metabolism can no longer keep pace with the energy demands of the muscles. These hydrogen ions form a part of lactic acid. The body falls back on this less efficient but faster method of producing ATP under low oxygen conditions. This is thought to have been the primary means of energy production in earlier organisms before oxygen reached high concentrations in the atmosphere between
Abdominal exercise Abdominal exercise Abdominal exercises are those that affect the abdominal muscles (colloquially known as the stomach muscles or "abs"). Abdominal exercises are useful for building the abdominal muscles. This is useful for improving performance with certain sports, back pain, and for withstanding abdominal impacts (e.g., taking punches). According to a 2011 study, abdominal muscle exercises are known to increase the strength and endurance of the abdominal muscles. It has been highly disputed whether or not abdominal exercises have any reducing effect on abdominal fat. The aforementioned 2011 study found that abdominal exercise does not reduce abdominal fat; to achieve that,