Warm up sets prepare your body for heavier weights. They are performed at lighter loads that gradually build up to your “working” sets. Jumping right to heavy weights will not make it easier.
Muscles become warmer – increasing activation and power output. Our joints move through the required range of motion for the exercise. And our central nervous system starts preparing for an increased demand.
Warm up sets are an opportunity to improve technique and mental focus. Performing light reps with intent will have carry over to heavier loads. Make each rep count – perform lighter reps with the same focus you would a heavy set.
Think preparation, not fatigue. We do not want to perform so many sets that we get tired – we just want to give our body time to get ready to work hard.