Once overlooked in the male dominated gym world, nowadays most gyms offer selectorized inner and outer thigh machines, some even benefiting from a total hip machine (so you can isolate your glutes as well).
Commonly, it's still mainly women performing adduction & abduction of the hips within the gym environment, in an effort for inner & outer thigh tone. Remember, you cannot spot reduce! If you have unwanted fat in this area, over performing inner & outer thigh exercises will make no difference! However, it's an exercise area which should not be overlooked, particularly with the lateral movement required within most sports. Of interest, a list of free gym workout routines for various sports and physique endeavors are available under the 'Workouts' category of the Gym Professor website.
Please find below a list of numerous leg exercises for isolating the muscles of the inner and outer thigh (adductors & abductors respectively).
Inner and Outer Thigh Exercises
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