Voluntary muscle strength and endurance: 'The mechanism of voluntary muscle fatigue' by Charles Reid

IN this study of the mechanism of voluntary muscular fatigue in man, isotonic contractions of the flexor sublimis digitorum (middle finger) were recorded by Mosso's ergograph. Results were compared and checked with those obtained from the recorded movements of a strong steel spring, the muscle in this contracting practically isometrically. The custom of flexing all three phalanges of the middle finger involves the use of a number of muscles, whereas if movement is joint, the main muscle involved is the flexor sublimis digitorum, Whether this limitation of the movement inducing fatigue allows of maximal contraction of the flexor sublimis digitorum is doubtful, but a number of experiments was carried out with the object of determining whether similar results were obtained where (a) movement was restricted to the first interphalangeal joint, or (b) flexion of all phalanges was employed. Beyond some difference in the character of the fatigue curves, the results stated in this investigation hold good for flexion of all three phalanges, for flexion of the second phalanx, and for all types of resistance used for isotonic and isometric contractions.