This rune allows the blessed to achieve feats that could only be achieved by the most accomplished of athletes, pushing their strength to what is humanly possible.
Due to this increase in power, tasks that were exhaustive before become easier. Only if the blessed has to use their full potential for an extended period of time will they become fatigued.
Where a man without the rune would be fatigued from lifting a crate, a blessed one would not be. However if he were to perform a task that would push his limits, he would be fatigued much in the way as a normal human would be.