Question

What is the source of the EMG (electromyography)?

How would the EMG differ for a person lifting a 1lb weight versus a 10lb weight?

Answer 1

The source of reading and and records in an EMG is the electric potential generated by the activation of muscle cells using various modes such as electrically or neurologically activated.

The electromyogram will show peaks of action potential very high in case of a 10 pound weight lift as compared to a 1 pound lift, in which case the muscle are not taking a lot of strain and very low contraction of muscles is taking place in the body. Here it has not been mentioned how the weights are being lifted so we can't go into the details of muscles being used for these lifts.