No. I take it that the steering is heavy?
Loose pump belt
Steering gear to column mis-alignment
Tires not properly inflated
Sticky flow control valve
Not enough pump pressure output
Excessive internal pump leakage
Excessive internal system leakage
Air in system
Obstruction in power steering lines
Binding front suspension ball joints or steering linkage
Incorrect steering gear adjustment
Excessive wear of steering pump internal parts
Steering gear valve sleeve or seals worn
Obstruction within steering gear.
Take your pick :)
One other thing, if you have your steering on full lock for more that about 30 seconds, that can cause your power steering to stuff up.