  The Parker hypothesis (Parker (1972)) assumes that heating of coronal loops
occurs due to reconnection, induced when photospheric motions braid field lines
to the point of current sheet formation. In this contribution we address the
question of how the nature of photospheric motions affects heating of braided
coronal loops. We design a series of boundary drivers and quantify their
properties in terms of complexity and helicity injection. We examine a series
of long-duration full resistive MHD simulations in which a simulated coronal
loop, consisting of initially uniform field lines, is subject to these
photospheric flows. Braiding of the loop is continually driven until
differences in behaviour induced by the drivers can be characterised. It is
shown that heating is crucially dependent on the nature of the photospheric
driver - coherent motions typically lead to fewer large energy release events,
while more complex motions result in more frequent but less energetic heating
events.
