Nerve pulses act by the rule "all or nothing", which means that their amplitude does not matter as long as it exceeds firing threshold.

I am sorry, but it is impossible to transfer all knowledge on this subject in this place. You should refer to textbooks on neuromuscular physiology, motor control etc.

Human muscles operate in a micro oscillatory fashion, even an apparently smooth and steady muscle movement is the resultant action of several concurrent contractions and relaxations, which is regulated by the frequency of action potentials. Not all muscle fibers in a given muscle is contracted simultaneously; even in full exertion, about one third of the muscle fibers will be firing contractions at the same time. So we can say that this process is about the frequency and pattern of action potentials.

Murat,

It is very hard for me as physicist to talk to bio people as all words have completely different meaning. I am trying to get a simple answer literally for 10 years. 

What do you mean by "frequency" please explain.

Thanks,

Mario

More proper is to talk about 'firing rate". Some people use the term "frequency", which I personally do not like, since as a physicist I reserve the word "frequency" for oscillations, such as e.g. alternate current. The interspike intervals of a neuron are not equal, but for a given excitation level they are distributed around certain mean interval. The reverse of this interval is the motoneuron firing rate. The higher the MN excitation, the higher its firing rate, and the bigger the muscle force. However, the proces of force generation is quite complicated, and it is impossible to describe it in a short notice. If you are really interested in the subject, you should look for books on muscle physiology (e.g. Muscles Alive by Basmajian). They are quite comprehensive for physicist, you can believe me!

Oh that's my line :-)

Whenever I inquire something related to physics I suffer the same nomenclature barrier. Frequency is simply frequency of the nerve impulses which propagate an action potential. If you require further elaboration I'll be happy to help. 

By the way, maybe you have a simple answer for my posted question as well, about the electrical properties of blood. 

Dear Maria and Murat,

Thanks for understanding ! So we are talking about mean pulse rate, that is number of pulses divided b the time of counting, and we silently assume that the process is stationary. Maria, I should definitely get a book on subject. But in the meantime. You said that the interinterval distribution (pulse waiting time distribution) is what, Gaussian? Or is it maximally stretched, exponential?

Is there a measurement of distribution of pulse waiting times, is it the same foe all people?