At what frequency does tetany occur?

Tetany refers to a sustained muscle contraction that occurs when the frequency of stimulation is high enough to prevent muscle relaxation between stimuli. The critical frequency at which this happens is typically around 30 to 50 pulses per second (pps). While it's important to recognize that different muscles and conditions may have slightly varying thresholds for tetany, 50 pps is generally accepted as the upper limit where sustained contractions begin to occur consistently.

At 50 pps, the muscle fibers are stimulated sufficiently to the point that they cannot fully relax between successive stimuli, leading to continuous contraction. This is a key principle in neuromuscular physiology, where higher stimulation frequencies produce stronger and more sustained muscle contractions due to the additive effects of each stimulus on muscle fiber membranes. Understanding this concept is essential for athletic trainers when considering both therapeutic modalities and the training effects of different types of muscle contractions.