In health and fitness, connectivity is a term that's used to describe how effectively and efficiently we can call upon our muscles to contract. When someone has great connectivity, their movement is fluid and their muscles can produce great control, stability, and force without being stiff or rigid.
Next time you go to the gym, look around and be very observant of the movement patterns of those around you. As you do this, ask yourself this question: "Does it look like they are working their muscles, or just moving the weight?"
Of course, moving the weight works your muscles, but does it work your muscles to their best potential?
Rather than focusing on the weight (number of pounds) you're using, think about your form and the contraction of the specific muscles being worked. Treat your exercises with this train of thought: "I'm going to contract ____ muscle in order to move my weight."
Over time, this will allow you to become more in tune with how your body needs to move in order to activate your muscle fibers.