Evaluation of methods for electrical stimulation of human skeletal muscle in situ.

A comparison was made between three different techniques for electrical stimulation of human skeletal muscle: percutaneous stimulation via large aluminum foil electrodes or via ordinary ECG-electrodes and intramuscular stimulation via platinum-coated wires.--The relationship between voltage and duration of the stimulating pulses and the evoked force of contraction is described.--A series of experiments on surgical patients who were curarized showed that these electrical stimulation techniques selectively activate nerve-endings within the muscle, and not the muscle fibres directly.--In a group of male volunteers there were linear relationships between body weight and maximum voluntary contraction force (MVC) of the knee extensors and between body weight and the stimulating voltage needed to produce 50% of MVC.