  We consider F-strings with arbitrary configurations in the Minkowski
directions of a higher-dimensional spacetime, which also wrap and spin around
$S^1$ subcycles of constant radius in an arbitrary internal manifold, and
determine the relation between the higher-dimensional and the effective
four-dimensional quantities that govern the string dynamics. We show that, for
any such configuration, the motion of the windings in the compact space may
render the string effectively tensionless from a four-dimensional perspective,
so that it remains static with respect to the large dimensions. Such a critical
configuration occurs when (locally) exactly half the square of the string
length lies in the large dimensions and half lies in the compact space. The
critical solution is then seen to arise as a special case, in which the
wavelength of the windings is equal to their circumference. As examples, long
straight strings and circular loops are considered in detail, and the solutions
to the equations of motion that satisfy the tensionless condition are
presented. These solutions are then generalized to planar loops and arbitrary
three-dimensional configurations. Under the process of dimensional reduction,
in which higher-dimensional motion is equivalent to an effective worldsheet
current (giving rise to a conserved charge), this phenomenon may be seen as the
analogue of the tensionless condition which arises for superconducting and
chiral-current carrying cosmic strings.
