How Can Muscle Strain Be Measured?

[Miopen]

I am trying to figure out if there is a way to measure muscle strain.

If I apply a force F to compress a hand grip to the maximum distance x

The work done to compress the hand grip is F*x

Work done = Fx

Since work done = energy used, I can change the equation to:

Energy used = Fx

When our muscles use energy to perform work, we get muscle strain. I can change the wording to:

Muscle strain = Fx

If I continue to hold on to the hand grip so that it would not spring back, I need to maintain the energy used. As time passes, more energy is used (no work is done) because I can feel that the muscle strain becomes muscle pain.

If I hold on to the hand grip for 10 s. Can I define the muscle strain to be:

Muscle strain = Fx * 10s (and the scientific unit is Nms)

I don't have to go into the cellular level to explain the various chemical reactions that take place to maintain the hand grip in compressed position. I just have to know the external force acting on my hand muscles.

I can't find any literature to scientifically measure muscle strain. Can I define muscle strain as such since no one has done it?

 

[jbriggs444]

Since work done = energy used, I can change the equation to:
[...]
As time passes, more energy is used (no work is done)

In fact, work done is not equal to energy used. Energy can be used to perform useful work or can be used and wasted. Chemical energy used by a hand straining without moving is wasted.