I am a huge big fan of resistance training and strength training but I disagree that barbell lifting is the one and only way or the best way to get strong. Barbell lifting isn't for everybody and it may not always be the most optimal way to maintain strength for everybody There are some serious limitations with barbell lifting which mostly have to do with the movement pattern that a barbell forces your body into. There are many other ways to maintain strength besides barbells. Another thing to consider is that strength without good mobility and good cardio is dysfunctional and useless. I thing older folks need to focus more on mobility and movement than just raw strength.