The pronated grip is the most common of the three weight lifting grips. It is also known as the overhand grip. It is a grip in which the palms are facing downwards and the thumbs are facing inwards. Simply put, you reach down and grab the bar, wrapping your hands around it and keeping your thumbs facing inwards.
Most people use the pronated grip exclusively. However, lack of variation in grip will deprive you of the benefits of using a reverse grip or a supinated grip. All grips work the muscles in different ways, mainly by targeting the muscles from a different angle. If one grip is used exclusively the muscles will adapt to it, and they will soon be doing the same amount of work with less effort. Varying the grip keeps the muscles guessing. Muscles that work harder, improve faster.