According to Russian Kettlebell expert, Pavel Tsatsouline,
“When you do something 5 versus 25 times it is a lot easier to keep your mind on the task at hand.”
He also says that, “Heavy weights command high respect while light ones do not.”
Concentrate on the exercise at that time.
Do your 5 reps at the correct intensity, and move on to the next task! This will hold your attention longer and you will not burn out or become board with your exercise plan.
Besides, lifting heavier weights allows you to develop awesome strength without training to failure. It actually ENERGIZES YOU!!