Neuromechanical matching also applies in maximum efforts, because the total amount of central motor command that we can generate at any one time is limited. We cannot increase the magnitude of the electrical signal in the motor cortex indefinitely.

This is why the bilateral force deficit happens. Motor unit recruitment is always lower in two muscles working at the same time compared to in each muscle working one at a time. Also, interpolated twitch studies show that muscles like glutes and quadriceps are maybe only 80% activated even when isolated in single-joint situations. Add on a few other muscles in a multi-joint exercise and activation is likely even lower.