Invited Editorial Magnetic muscle stimulation produces fatigue without effort

impairments in performance are associated with increased mortality (6, 9, 10). Although muscle strength and endurance can be assessed with voluntary exercise, measurements can be confounded by changes in the way the muscle is driven by the nervous system and by cardiorespiratory limitations. A means to measure muscle strength and endurance without volition could allow useful assessment of muscle properties and their importance independent of systemic influences. To determine the fatigue properties of isolated muscles, the muscle is stimulated at a predetermined frequency, and the decline in force produced by a constant stimulus to the muscle is mea-sured. To fatigue human muscles is often less straightforward. They can be fatigued by voluntary activity and the fatigue mea-sured as either a decrease in force produced by a maximal voluntary contraction or as a decrease in the twitch force produc