Take a zercher hold on your keg and keep the keg right under the chin, upper body stays upright
many people do not hold the keg high enough and allow their body to drop downward, which takes stress away from your entire back working hard!
the water moving around the keg will add a good 10 - 20 lbs easily.
any lunge is possible here: walking, forwards and reverse
this is a very economic movement because the upper body works quite intensely as well as the legs