Generally, higher volume training has a propensity to increase muscle size and lower volume training will increase muscle strength and density.

This is not to say that when doing strength training you will not gain size or when doing volume training you won't gain strength. There is no "line in the sand" where one stops and the other starts. Just for the sake of conversation/argument, however, some say that a 5x5 program is a good "middle ground" for strength and size.

IW