"Quality mass" refers to a state or condition of having a significant amount or quantity of something, while also ensuring that it is of high value or good quality. Full definition
Rather than having to tackle several chicken breasts or steaks at each meal, you should instead seriously consider investing in a good quality mass gaining supplement. (aretheyonsteroids.com)
Because this time of year the focus is on building quality mass to show off next summer. (sixstarpro.com)
If you want to gain only quality mass, aim to increase * the size of your meals after training or during breakfast when your muscles crave for more calories and nutrients. (consumerhealthdigest.com)