Hip abduction and adduction machines: the outer and inner thigh machines, set up and explained

Most gyms have the pair side by side, and often it's one machine with pads you flip. On the hip abduction machine you push your knees apart against pads on the outsides of your knees; on the hip adduction machine you squeeze them together against pads on the insides. Abduction trains the muscles on the side of the hip: the gluteus medius and gluteus minimus, the upper part of the gluteus maximus, and a smaller muscle at the front, the tensor fascia latae. Adduction trains the inner thigh, the adductors.

Neither is a main lift. Squats, hinges and lunges come first in the leg day; these two add work to muscles those lifts reach less, or differently. This page covers the setup for both, what each one trains, what training on them did in the studies, the alternatives without a machine, the faults, and the sets.

How to use them

The hip abduction machine

1. Set the pads so your legs start together, or a little apart if the machine won't close further.
2. Sit all the way back, hips against the back pad, the pads on the outsides of your knees, hands on the handles.
3. Push your knees apart as far as you can without your hips lifting off the seat or your back rocking.
4. Hold for a moment, then let the pads come back in about two seconds, stopping before the weight stack touches.

The hip adduction machine

1. Set the starting width where you feel a mild stretch on the inner thighs, not more. Start narrower than you think and widen it over a few sessions.
2. Sit back with the pads on the insides of your knees.
3. Squeeze your knees together until the pads meet or nearly meet.
4. Return slowly to the starting width, about two seconds, and go again.

What the abduction machine trains

• The side glute, about as much as the floor versions. In 11 men doing ten maximal reps of each, gluteus medius activity showed no difference between the abduction machine, side-lying leg raises and the clamshell. The tensor fascia latae worked less on the machine than in the side-lying raise, so the machine had the highest ratio of gluteus medius to tensor fascia latae activity of the three.¹
• A band can ask more of it. In 16 untrained women, a hip abduction with an elastic band produced more gluteus medius activity than the abduction machine.²
• Where the machine sits in the bigger picture. A 2015 review of 23 studies of hip abduction and rotation exercises found the highest gluteus medius activity in a side plank with the top leg raised, a standing abduction with a band at the ankle and side-lying abduction, 81% to 103% of a maximal contraction.³

Activity is measured during a set; it isn't growth over weeks.

What training it did

One trial trained the movement for weeks. In 17 young adults, each trained one leg with a cable hip abduction and the other with a cable hip extension, twice a week for ten weeks, about ten sets a week of 8 to 12 reps. On MRI, the abduction leg grew the gluteus maximus by 5%, mostly in its upper part, 10%, and the gluteus medius and minimus together by 4%. The hip-extension leg grew the gluteus maximus more, 9%, but the medius and minimus by 2%. Each leg's strength rose most on the exercise it trained: 35% on the abduction max for the abduction leg, against 17% for the other.⁴ The trial used a cable, not the seated machine; no trial of the machine itself turned up in a PubMed search for this page.

That matters next to the big lifts. In a nine-week trial of 34 untrained young men and women training either back squats or hip thrusts, the gluteus medius and minimus showed little to no growth in either group.⁵ Read side by side, two different trials suggest that direct abduction work grew the side of the hip a little, where the squat and the hip thrust didn't. The hip extension half of the same trial is on the glute kickback.

What the adduction machine trains

• The adductors, about as much as a band. In the same 16 untrained women, an adduction with an elastic band and the adduction machine recruited the adductors about equally.²
• The biggest adductor mostly extends the hip. In 15 young adults, imaging of the adductor magnus, the largest inner-thigh muscle, showed that over 80% of its volume sits in the parts set up to straighten the hip, and that its capacity to produce torque was more than twice as great for hip extension as for adduction.⁶ So the biggest inner-thigh muscle is built to help in squats and hinges too, not only when you squeeze.
• Squats grow them. In 17 men over ten weeks, full squats grew the inner thighs more than half squats, 6.2% against 2.7%.⁷ In the nine-week trial above, the squat group's adductors grew more than the hip thrust group's.⁵
• Lying on your side beats the sumo squat for one of them. In 24 physically active college students, side-lying hip adduction produced the most activity in the adductor longus of six exercises aimed at the inner thigh, with ball squeezes second and the sumo squat last.⁸

So for the inner thighs, deep squats already do a lot. The adduction machine adds direct work if you want more; it isn't required.

Alternatives without the machines

Every exercise in the table is one the studies above measured during a set; none was tested over weeks of training there. They're the same two jobs without a weight stack.

The common faults, and a fix for each

• Rocking the body to move the weight. If your back leaves the pad, it's too heavy. Sit back and go lighter.
• Half reps. Use the range you can control on every rep, and pause where the pads stop.
• Letting the stack slam. Two seconds back, every rep.
• Starting the adduction machine too wide. Begin with a mild stretch and widen it over a few sessions.
• Making them the main event. They come after squats, hinges and lunges, not instead of them.
• Training through something that hurts. Sore muscles the next day are normal; anything sharp or lasting isn't. Stop, and see a doctor or a physical therapist.

Sets, reps and where they go

• Two or three sets of 10 to 15, stopping with a rep or two left. (How to judge reps left.) The American College of Sports Medicine's 2026 position stand, which covers healthy adults, advises at least two sets per exercise.⁹
• At the end of a leg or glute session, one or both. In the glute workout, abduction fits as a sixth exercise.
• Progress by adding reps to the top of the range, then a plate. (Progressive overload covers the options.)

If you'd rather not plan it alone

These two machines are easy to use; deciding whether your week needs them on top of the squats and hinges, and how much, is the part a page can't do. Coaching is the version where your workouts are built around the days you actually have, and a weekly call looks at the week you just had and rebuilds the next one. Coaching to build muscle explains how that works, and here's how to apply. Otherwise: at the end of your next leg day, do two sets of 15 on the abduction machine, pausing with your knees apart, and write down the weight.