The way I visualize it is by the shape of the bump and rating shaft speed on a scale of 0 - 10.
A rolling trail (wavy roller coaster) will affect LSC. This type of bump makes the shaft move from zero to 10 very slow.
A sharp hit will affect HSC. This type of bump makes the shaft move from zero to 10 pretty quick.
Of course this is a very simplistic way of looking at it as there is more to it than that, but its a starting point to understanding it.
A rolling trail (wavy roller coaster) will affect LSC. This type of bump makes the shaft move from zero to 10 very slow.
A sharp hit will affect HSC. This type of bump makes the shaft move from zero to 10 pretty quick.
Of course this is a very simplistic way of looking at it as there is more to it than that, but its a starting point to understanding it.