I've been working most muscle groups twice per week for the last several months but due to time constraints, I'm thinking of dropping it to only once, something like:
Mon - chest/triceps
Wed - back/biceps
Fri - legs/abs
Assuming I eat the same (currently a little over maintenance,) and that I use the same weights, what will the effect be of switching to this?
I do it twice, but combining back and chest/shoulders/tris on the same day. legs/gluts/low back gets twice a week as well.
It's hard to say how it will effect you. It could be good for you - a change up. Give it a shot and see what happens. Remember, giving it a shot is several weeks worth of the same routine, not just 1 or 2.
Give chalk a chance.
49 years old
Or are you going to cut your volume in half b/c you're doing your same workout but only doing it once a week instead of twice? This means you've cut your workload in half. What will this do to you?? You'll only know after you try it. You might explode b/c you'll have more recovery and you'll be able to lift heavier b/c you're only lifting once a week per 'bodypart.' OR it might not be enough training stimulus to generate gains, in which case you'll stall. It depends on a lot of variables, including your training experience.
Typically, a cut in workload and frequency, which is what it sounds like you're doing, will mean less stimulus, which might mean fewer gains. It depends how your body reacts.