At the microscopic scale, the situation is the one of low Reynolds numbers, with inertial forces neglected with respect to
viscosity.

Therefore the hydrodynamics of the system are governed by the Stokes equation, and the dynamics of the swimmer follow the Newton laws
without inertia.

Resistive Force Theory (RFT) provides a local drag approximation, assuming that the force exerted on the swimmer by the fluid is linear
with respect to velocity. In this framework, the dynamics of the N-link swimmer in a plane can be expressed as an ODE, which allows to find
the optimal swimming strategy for different objective functions such as maximal displacement or efficiency.

It can be proven and checked in the simulations that optimal solutions
are typically sequences of periodic strokes.

https://www.bocop.org/micro-swimmer-in-low-reynolds-number-fluid/