Theres so much debate about the optimal frequency in which an individual should hit the gym. Is it best to go 3 times a week?  maybe 5? How about 6? some even claim as little as 1! See the truth is...There is NO optimal training frquency. The best way i have dicovered to explain to people is something I picked up from a famous strength and conditioning coach. "An individual should train as often as possible without exceeding their aility to recover". Simpily put this means that you should train as much as you can as long as you can recover from the previous session. If that means training once a week or 20 times a week then so be it. The more frequestly you train and recover from that training the faster you will progress and achive results. So your focus should be on increasing your work load from week to week, especially if gaining muscle mass is the goal, in that case you should bumb up the volume as well as the weight used in excerises.