Ontario U14, barefoot PowewTraining on the Fieldturf™
The advantage of the water barrel is it creates consistent drag so competition between players is created by how well they shift the 7's Powertraine with the same weight.
Some schools have purchased three barrels colour coded them with some paint then filled the barrels with varying amounts of water/weight. then when they use they roll on the correct one for the age group that is training.