CNS Fatigue VS Pheripheral Fatigue

CNS Fatigue VS Pheripheral Fatigue
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“When we exercise, we often experience a temporary (and reversible) reduction in strength, which is called “fatigue.” Fatiguing mechanisms can occur at many points in the sequence of events by which we produce muscle force (from the brain to the actin-myosin crossbridges inside muscle fibers).⁣⁣
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When fatiguing mechanisms occur in the brain or spinal cord, they cause CNS fatigue, and when they occur inside the muscle, they cause peripheral fatigue. ⁣⁣
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Some forms of exercise (such as those of longer duration or which involve more fatiguing sensations) cause proportionally more CNS fatigue, while other forms of exercise cause less.⁣
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When CNS fatigue is triggered, muscles still abide by the size principle. The first motor units to be affected by CNS fatigue are the highest-threshold ones, which control the most responsive, highly-adaptable, fast twitch muscle fibers. ⁣⁣
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Peripheral fatigue only affects the working muscle fibers. Thus, CNS fatigue has a much more negative effect on our ability to stimulate hypertrophy than peripheral fatigue.⁣⁣⁣
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Likewise, fatiguing mechanisms inside the muscle during exercise can involve both metabolite accumulation (which is quick to occur, but also quick to reverse) and calcium ion overload (which is slow to occur and to reverse), and the proportion of each depends on the exercise. ⁣⁣
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This has a large impact on the time that the muscle then takes to recover from the workout, and explains why eccentric contractions take so much longer to recover from than concentric and isometric contractions.” ⁣⁣⁣