A lot of powerlifters have taken notice, because the total amount of weight they could lift was being limited by their work capacity. By doing G.P.P (General Physical Preparedness) aka sled work powerlifters were able to train different energy systems... although sled drags are not sport specific to powerlifting it indirectly increases work capacity, allowing for increased total weight lifted!
What can the normal athlete take from all this? By adding a reasonable amount of G.P.P to your weight training sessions you can go a long way towards a stronger, leaner body, with a better ability to recover. The weight sleds they use at strength and conditioning facilities can be expensive thats why I want to link you to this article on how to make a home made weight sled... Isn't much to look at but these things are torture!
Here is a brief clip from my workout today on a home made weight sled