Three main forces are considered for this calculation: gravitational,\(F_{g}\); friction, \(F_{f}\); and drag, \(F_{d}\). In GTA, friction is
disregarded, as it represents only a small fraction of the power; also,
the losses, \(l\), mainly represented by the friction of the chain and
other mechanical components of the bike, are negligible.
Obviously, the speed used in this equation has no relationship with the
velocity used to update a particle’s position. Here, the speed is
calculated through Eq. (7), representing the cyclist ascending or
descending (vertical) speed, using two consecutive values of the
cyclist’s objective function (OF ).