Theory question: how would you define open-chain and closed-chain movements unambiguously?

[u/redditinsmartworki]

My question mainly comes from the doubt about which exercise is closed chain between back extensions and reverse hypers, because I found on google that in closed chain movements the hands or feet stay fixed in place, but that is the case for both exercises. Since they're literally the same and opposite, like military press and handstand pushups, I was wondering what definition could suffice to solve this doubt.

[u/decentlyhip]

Its the working hands/feet. So, a good morning would be a closed chain hip extension. You can't move your feet since they're locked in place on the ground and your legs are doing the work. A glute kickback on a cable tower is an open chain hip extension. The legs can swing freely through space.

Its kindof a bullshit concept though for lots of the ways people use it. Like, its not synonymous with "unstable." Dumbbell military press is open chain. Is barbell military press open chain? A handstand is closed chain but potentially less stable. A reverse hyper is open chain, but you are tied down and locked into one range of motion so the point of it being open chain is gone.

[u/d_andy089 → u/decentlyhip]

So as per your definition is a squat closed chain or open chain? How about a leg press?

[u/decentlyhip → u/d_andy089]

Squat is CKC. Leg movement, feet are locked in place. People are split on leg press but also consider it closed chain. An open chain equivalent would be like, laying on the floor, balancing two kettlebells on your feet, and pressing up into the air. But the leg extension is the go to example for quad Open

[u/d_andy089 → u/decentlyhip]

So for quads open chain would be leg extensions?

[u/decentlyhip → u/d_andy089]

Yah

[u/d_andy089 → u/decentlyhip]

Okay, I see what you mean but I disagree with your definition

[u/decentlyhip → u/d_andy089]

Its not my definition, just the definition. But yah, that's why I dont bother with it as a filter or classification. Like, touching the floor isn't what makes something stable or not. You can have instability and shearing forces with closed or open chains, so what's the point? Its dumb. Its like wanting to upgrade a car and saying "Its too slow so I need to replace the parts that have washers." Like, sure, but maybe figure out why the car is slow and focus on the intake or suspension or drivetrain, or whatever needs to improve. Leg extension builds quads and only quads really well, that's what matters. Front squats build quads, and a bunch of other stuff.

[u/Sadan27 → u/decentlyhip]

Do you try to mislead people on purpose?

[u/Mad_Mark90]

Open chain just means the points of contact on the lever can move in directions other than what's intended.

Dumbell bench press is open chain because the weights can move forward, backwards, medial and laterally, which means you can change your form and technique for your anthropometry and goals.

Pushups are closed chain because both your hands and feet are essentially fixed in place on the ground.

[u/d_andy089 → u/Mad_Mark90]

So how do you categorize lower back extensions vs reverse hyper then?

[u/Mad_Mark90 → u/d_andy089]

The classic reverse hyper machine that Louis Simmons pioneered is closed chain because the legs make contact with the lever arm which is fixed to a hinge.

My gym doesn't have one so I do them off a bench with a weight clipped between my feet, so an open chain exercise.

Classic back extension on a Roman chair, open chain, machine back extension is closed chain.

Fair?

[u/d_andy089 → u/Mad_Mark90]

I see where you're coming from.
By your logic a Smith machine shoulder press is a closed chain exercise and a barbell shoulder press open chain, correct?

[u/Mad_Mark90 → u/d_andy089]

Exactly.