Exercise physiology loss of integrity to the blood brain barrier. Hyperthermia also can lower cerebral blood flow, and raise brain temperature. Researchers once attributed fatigue to a build-up of lactic acid in muscles. However, this is no longer believed. Rather, lactate may stop muscle fatigue by keeping muscles fully responding to nerve signals. The available oxygen and energy supply, and disturbances of muscle ion homeostasis are the main factor determining exercise performance, at least during brief very intense exercise. Each muscle contraction involves an action potential that activates voltage sensors, and so releases Ca ions from the muscle fibre’s sarcoplasmic reticulum. The
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,