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
Asynchronous muscles These systems can be thought of as resonant systems, for which the oscillation frequency is dependent on the elasticity, damping, and force applied to the system. In a simplified case, this can be thought of as a linearly damped harmonic oscillator, for which the damped resonant frequency is formula_1 The damping ratio, "ζ ," is dependent on c, the damping coefficient, m, the mass of the system, and k, the stiffness of the system as shown formula_2 Asynchronous muscles sacrifice neural control and flexibility in exchange for high force production and efficiency. Given the long twitch duration of asynchronous muscle,