If you have a one-wheeled wheelbarrow then you will, on average, be supporting half the weight of the load in your own hands. But if you have a four-wheeled barrow, or cart, you will not need to support ANY of the weight of the load. All you will need to do is push and overcome the resistence between the wheels and the ground. So if you have decent paths then get a decent barrow. A one-wheeled barrow is only for narrow paths and irregular ground.