Ultimately, it’s not just what you do in the Gym that will help you gain mass. What you do out of the Gym is of at least equal importance. When I read about someone grappling three days per week I wonder exactly how long and intense these grappling sessions are. How much energy is expended relative to caloric output.
If the question is “can someone gain mass training only twice per week.” The answer has to be yes…but…
Some helpful thoughts.
What sort of body the trainee brings to the situation. Are they ectomorphs, endomorphs, mesomorphs? I used to work at a bar with a guy who played basketball 5 times per week worked two jobs and still gained muscle! Rare I bet.
What other activities are you doing outside of your weight training? You stated grappling. Are there any others?
What sort of “stress” do you have in your life? Married with kids? Single going to school with a huge study load?
Stress manifests itself in many negative ways…not good for muscle growth, nope.
What sort of caloric intake do you have per day? Eat on the fly a lot, or are you “eating clean?”
How is your protein intake? Are you slinging down about one gram per pound of body weight daily? That is not easy to do without a quality protein supplement like Grow!
Are you sleeping at least 8 to 9 hours per night? I have noticed (and I think there have been a few studies) that you can be on the perfect diet and program, but if the quality of sleep is low you don’t gain. Funny how it all works together huh?
Under the right conditions you can indeed add muscle mass with only two sessions per week. Although I doubt if it is ever the ideal.