I have a question regarding how molecular interactions manifest in physical actions - such as hanging from a bar. To the best of my understanding, when it comes to the contraction of muscles, ATP is required for myosin to detach from actin - terminating contraction.
So, what I'm wondering is when we are hanging from our bar, utilizing our grip strength, we are in a constant state of contraction. However, eventually, our muscles fatigue and we let go. I presume this is because we are running out of energy, but isn't energy (ATP) what was necessary to terminate contraction? Why do we eventually let go of the bar and how is this represented on the scale of muscle fibres?