Linear Tangents

Whilst animating I started to notice that when my character placed his foot down and the moved forward, his foot would slide back a little, or would rotate slightly the wrong way then carry on the way it was meant to go. I decided to look into the graph editor and sure enough i noticed a slight spike in the corresponding transfer or rotation. To remedy the problem I decided to change the error prone tangents into linear tangents. To do this I selected the problem causing points in the graph, clicked 'break tangents' (as they were currently unified) and then select one of the tangent's weights so that I could then click 'linear tangent' which changed the spikes in the graph to be flat.

It can be better explained by the images below:

After the tangent was changed to a linear one, the problem was solved and the foot no longer rotated abruptly and in the wrong direction.