EXCITATION OF MUSCLE |., ; 



stimulus is ineffective ; so in both cases, whether we make or break the 

 current in the primary circuit, we are dealing with a make stimulus in the 

 muscle. The difference in the efficacy of make and break induction shocks 

 is purely physical, and depends on the fact that the current induced in the 

 secondary coil on make is of slower rise and smaller potential than that 

 produced at break. 



In using either of these modes of stimulation we find that there is a certain intensity 

 which the stimulating current must possess in order that any effect shall be produced. 

 Any strength of stimulus below this is known as a subminimal stimulus. A minimal 

 stimulus (sometimes known as liminal or threshold stimulus) is the weakest stimulus 

 that will produce any result, i.e. in muscle, a contraction. A maximal stimulus is 

 one that produces the strongest contraction a muscle is capable of under the effects 

 of a single stimulus. A submaximal stimulus is any strength of stimulus between these 

 two extremes. 



