Protein shake,high reps,low reps,heavy ass weight,the list going on and on.If YOU follow the S.O.A.P principle that i going to talk about now,i pretty sure YOU are able to gain some solid muscle in no time.

S=Specificity
O=Overload
A=Adaptation
P=Progression

Specificity
-This is when training replicates the movement and energy system that involved in for that sport or activity.

Overload
-The weight must be overload.To elicit optimal adaptation and prevent injury,overload must be individual and progressive.

Adaptation
-In order for a workout to improve ,it has to undergo a necessary adaptation,before any changes done to a workout program.

Progression
-The gradual increase in load and intensity of trainings .Increase in the number of reps,decrease resting time etc.

If you workout doesnt adapt to either one of the principle above,u might wana consider to do so.If not, u might be losing the biggest opportunity that able you to build up solid muscle.