Since I get this question almost daily, I figured it would make a good topic. First just realize there isn’t really any one “best” exercise for one muscle especially since you never use only one muscle during an exercise, and you never use one muscle in only one way. That’s not how your brain and body work together.
Anyway, I get the question all the time and instead of explaining all the intricacies of exercise and trying to convince people of certain things, I try to just keep it simple and give them an exercise. I’ve found the less I talk, the better.
So, today’s bodypart is…the inner thighs! First, let me tell you that the inner thigh machine where you sit on your ass at you local fitness center is not your best option because you are…. sitting (duh).
A few of the best exercises for your inner thighs are forward lunges, walking lunges, and stiff-legged deadlifts. Actually any single leg exercise performed through a full range of motion (thighs below parallel) while standing is great for your inner thighs but we’ll narrow it down to lunges.
The inner thigh muscles function both as adductors (brings your knees/thighs inward) hip extensors and hip flexors. It all depends on the position of the hip joint. For instance, during running they would function as lateral stabilizers (along with some other muscles) during the stance phase, then as hip flexors during the forward stride of that same leg, and then as extensors as you pull your leg back under you.
When you lunge, if your knees are in the proper position of being aligned with you middle toe, then your glutes and adductors are counteracting each other resulting in good knee and hip alignment, which then leads a stronger, more stable lunge. So the adductors have more than one function during the lunge or during running as opposed to a single non-functional action while using the seated inner thigh machine (don’t forget, your “core” is not being utilized while on the seated inner thigh machine either meaning lower calorie burn and less EPOC).
You may notice you get very sore after performing lunges, especially forward and/or walking lunges. This is because there is a very high eccentric and deceleration component to these lunges which is usually what is responsible for most of the soreness.
One other thing, you may have heard “don’t let your knee of the front leg go to far forward” and certainly not beyond your toes. I wouldn’t be too concerned with that. From what I know it’s never been proven and I have never had any trouble with it myself or with my clients. I would be more concerned with the knee of the front leg rotating inward. This is usually a sign of weak glute medius (hip muscle), possible weak VMO (muscle medial of kneecap), tight ankles (limited dorsiflexion), or foot pronation (fallen arches). Address those issues before getting into any serious leg work.
So if you want to hit those inner thighs, get on your feet and off your ass. Get some lunges in, some single leg exercises, some deadlifts. All are much better options then the seated contraption you find at most fitness centers. You’ll get the added bonus of these exercises also working your glutes, hamstrings, quadriceps, calves, core, and resulting in more calories burned both during and after exercise.