Pedal Force is the Force applied to the pedal.
At the moment no power meter directly measures the force(s) applied to the pedal. It is possible to derive the average (i.e., over 360º) effective (i.e., tangential to the crank) pedal force (both legs combined) from power and cadence data as follows:
AEPF = (P*60)/(C*2*Pi*CL)
Where AEPF = average effective pedal force (in N), C = cadence (in rev/min), CL = crank length (in m), and the constants 60, 2, and Pi serve to convert cadence to angular velocity (in rad/s).