The hip adduction machine — the one where you squeeze your knees together — is one of the most-used and most-misunderstood pieces of equipment in any gym. Here's the honest guide. The hip adduction machine trains your inner thigh muscles effectively enough, but it can't spot-reduce inner-thigh fat, and weight-bearing adductor exercises transfer considerably better to real movement.
What it actually trains (the honest mechanics)
Seated with your legs apart and pads on the inside of your knees, you squeeze your legs together against resistance. This trains the adductors — the inner thigh muscle group that brings your legs toward the midline and, importantly, stabilises your hip and pelvis during walking, running, and single-leg movement. The machine loads them directly and progressively, which is a legitimate benefit: it's easy to set up, easy to add weight, and requires no technique. It's the mirror image of the hip abduction machine for the outer hip.
The spot reduction myth (the honest answer)
This needs saying plainly, because it's why most people use this machine: you cannot burn fat off a specific body part by training the muscle underneath it. Doing hip adductions to lose inner-thigh fat doesn't work — spot reduction isn't a thing, and the research on it is consistent. Fat loss happens across your whole body in response to a calorie deficit, and where you lose it first is largely down to genetics. What the machine can do is strengthen and develop the adductor muscles. If your goal is leaner inner thighs, the honest answer is: overall fat loss through nutrition, plus resistance training for the whole body — not high-rep adduction.
Is it worth using? (the honest assessment)
A fair verdict on both sides. The case for: it loads the adductors directly and progressively, requires no skill, is safe, and provides a genuine strengthening stimulus for a muscle group most people never train. That's not nothing — weak adductors are common and adductor strength matters for hip stability and groin injury risk. The case against: it trains the adductors seated and non-weight-bearing, in an isolated movement they rarely perform in isolation. Their real job is stabilising your hip while you're standing, running, and changing direction — which sitting on a machine squeezing pads doesn't rehearse. Honest verdict: useful supplementary loading; not the best adductor training available.
Better adductor exercises (the ones that transfer)
If you want adductors that actually do their job, prioritise these. Copenhagen planks — the gold standard, loading the adductors while stabilising your body; associated with reduced groin injury risk in the research. Cossack squats — a deep lateral squat that loads the adductors through a big range. Wide-stance squats and sumo deadlifts — both load the adductors as part of compound movements. Lateral lunges — weight-bearing adduction and hip control. Sliding leg adductions — with sliders or towels on a smooth floor. Honest guidance: make these the priority and use the machine as supplementary direct loading if you like.
How to use it properly (if you do)
Straightforward, with a few points. Adjust the pads to sit against the inside of your knees and set the starting width to a stretch you can control — don't set the widest possible starting position and then force it, since the adductors are strain-prone tissue. Then squeeze your legs together under control, pause briefly, and return slowly, resisting the weight rather than letting it snap your legs apart. Keep your back against the pad. Use moderate weight for 10–15 controlled reps — this is not an exercise to ego-load, both because the muscles are relatively small and because a rapid forced stretch under load is how groins get strained.
Where it fits (pair accordingly)
Use it as a supplementary accessory, 2–3 sets, on a leg day. Pair it with hip abduction work for the outer hip — training one side without the other creates imbalance — plus Copenhagen planks for the weight-bearing version and adductor mobility. For athletes doing lateral work, treat adductor strength as injury-prevention training rather than aesthetics. Progress with progressive overload, but modestly.
Quick answers
What does the hip adduction machine work?
The adductors — the inner thigh muscles that bring your legs together and stabilise your hip.
Will it slim my inner thighs?
No — spot reduction isn't possible; inner-thigh fat comes off with overall fat loss from a calorie deficit.
Is the machine worth using?
It's useful supplementary loading, but weight-bearing exercises like Copenhagen planks transfer better.
What's the best adductor exercise?
The Copenhagen plank, plus Cossack squats, lateral lunges, and wide-stance squats.
How much weight should I use?
Moderate — 10–15 controlled reps; forcing a heavy stretch risks a groin strain.
Should I train adduction and abduction?
Yes — training one without the other creates imbalance.
Why train adductors at all?
Hip stability and groin injury risk — they're commonly weak and rarely trained.
The inner-thigh machine will strengthen your inner thighs. It will not slim them — and no amount of reps changes where your body decides to lose fat.
The hip adduction machine is a reasonable way to load a commonly-neglected muscle group directly, and a poor way to chase leaner inner thighs. Use moderate weight with controlled reps, pair it with abduction work for balance, and make weight-bearing exercises like Copenhagen planks and lateral lunges the priority. Fat loss comes from a calorie deficit, not from the machine.