Closed chain exercises are those exercise where the end of the chain is “connected” to not-movable object (with great mass) usually ground (squats, lunges…) or bar (pull up, chin up, dips, push-ups).
Open chain exercises are those exercise where the end of the chain is “connetced” to movable object (leg extension, leg curl, pull-down etc).
The problem arises because the chain have two ends! So you can consider squat as closed chain if you reffer to legs, and open if you reffer to shoulders as “chain ends”!
Usually, closed chain exercises for the legs are considered more “functional” than open ones, because your legs are allways connected to ground (except for kicking).
This this can go into futher discussion, especially regarding what should be considered closed and what opened, what should be considered functional and what not… etc… etc…
That’s precisely the arguement I was getting at! The words “functional” and “sport specific” are never far behind in this type of discussion.
Use the training you’ve found to be safe and effective and avoid arguements over semantics and “flavour of the month” training methods .
When I start to hear things like, the differences between the open vs closed chain exercise would require a whole new article, or the recruitment patterns vary, I began to question if I was missing something.
My thinking was more about what would be best for the athlete without the whole functional, comes from the core, one set to failure, primal movement pattern type of thing.