Hello Khalid.

I like this question as its a genuinely interesting one. I will assume you are talking about muscle fibres within a healthy participant., i.e. they do not have any neurological conditions causing a clonus, tremor or high tone/ spasticity. Nor would the person have any regional pain, which may cause 'guarding' of a joint(s). A tight muscle is one that is unable to relax normally, therefore will have an increased base value and EMG signal, therefore may be incomparable to a normal sarcomere. A tight muscle will also be a weak one, meaning that peak values will be more difficult to attain. Therefore it will still record its Fpeak and Fmean but these will be anomalies with data from non-tight muscle fibres. I hope that helps, though I feel there is something you haven't quite asked/ I haven't fully understook from the question. :)

Hello Khalid.

I like this question as its a genuinely interesting one. I will assume you are talking about muscle fibres within a healthy participant., i.e. they do not have any neurological conditions causing a clonus, tremor or high tone/ spasticity. Nor would the person have any regional pain, which may cause 'guarding' of a joint(s). A tight muscle is one that is unable to relax normally, therefore will have an increased base value and EMG signal, therefore may be incomparable to a normal sarcomere. A tight muscle will also be a weak one, meaning that peak values will be more difficult to attain. Therefore it will still record its Fpeak and Fmean but these will be anomalies with data from non-tight muscle fibres. I hope that helps, though I feel there is something you haven't quite asked/ I haven't fully understook from the question. :)

please see

https://benthamopen.com/contents/pdf/TOREHJ/TOREHJ3-110.pdf

It is an interesting question. I believe Chris Mulvaney has answered it eloquently. The EMG base value will shift toward either positive or negative direction, and I also presume the EMG values to be lower than

Hi Khalid,

You mentioned: "Muscle tissue does not normally produce electrical signals during rest". Actually, you can pick up an electrical signal during rest, which is called muscle tonus. Muscle tonus has numerous benefits including balance, posture, muscles are prepared for action, joint stability, etc.

Also, I am not quite sure whether your question is about invasive or non-invasive (measurements on the skin surface) EMG. It will not be possible to make any claims regarding the EMG amplitude as for surface EMG this depends on many different factors (muscle of interest, skin temperature, fat tissue, hydration of the participant, sweat, electrode material, electrode configuration, electrode diameter, distance of electrodes to the muscle and innervation zone, ...).

I feel like you are overthinking the question. You will be able to see EMG activity greater than EMG activity at rest in case there is an electric input from the neurons innervating the muscle of interest (i.e. active motor units). There may be several neural (affecting EMG; e.g. hypertonia, cramps) and non-neural (not affecting EMG; e.g. incrased extracellular mass) reasons for increased muscle stiffness. Thus, keep in mind only neural contributions to increased muscle stiffness will affect EMG. The final answer to what an EMG system will detect when recording signals from a stiffer than normal muscle is: That depends. :)

Hope that helps!

Thank you, Lukas Wiedemann...it is as though you read my mind and wrote what I was thinking. Your contribution here is very important. Without this understanding, we misinterpret EMG.