The abductor and adductor machines are the ones that work your inner and outer thighs. These two machines are basically a joke to any muscle head because of how awkward they look and the claim that they are a waste of time. This is not all true. Yes the act of the machine may seem a little uncomfortable because the opening and closing of your hips but they actually do a lot of good.
These two workouts are isolation workouts meaning they don’t target multiple muscles all at once. They should be used to target specific problem muscles that you need to work on without working your stronger muscles. This helps you to learn how to tighten the specific muscle so you can help to isolate in other workouts.
So how do you know when to use them?
Athletes can focus on their adductors and abductors for better lateral movements, quicker sprints and higher jumps. Having tight hips can prevent the quality of your squats. Being able to open your hips allows you to squat lower, working more compound muscles than small, tight squats. Using the abductor machine gives an instant booty pump working all three of your glute muscles.
You will need to mix the sitting ab/adductor workouts with standing workouts to make sure range of motion is being pushed to really benefit your muscles. So yes, they are worth your time as long as you are using them to isolate problem muscles. If you aren’t targeting, then you will not see a growth of muscles because obviously ab/adductor muscles are not visible muscles.