Mixed

For recreationally resistance-trained men, performing a split-body resistance training routine with 2 sessions per week per muscle group yields equivalent maximal strength and muscle hypertrophy gains compared to 3 sessions per week, provided total weekly volume is equated.

If you are an experienced lifter, you don't need to train every muscle 3 times a week to maximize gains. You can split your routine over 2 days per muscle group (e.g., 9 sets per muscle per session, twice a week) and get the same strength and muscle growth as training 3 times a week (6 sets per session), as long as you hit the same total weekly volume and train hard.