Joshua Reynolds and Maris Ambats deserve credit for inventing the mood ring, a liquid crystal that responded to variations in body temperature by changing color. That was in 1975. Reynolds’ 15 minutes of fame was extended to 30 when, in 1990, he invented the Thighmaster.
Championed by actress Suzanne Somers, this spring-loading exercise device was supposedly a breakthrough in working the inner thigh muscle group called the adductors. The product was launched in the summer of 1991, and 18 months later six million Thighmasters were sold. But to train the inner thighs, is it really necessary to purchase an “As Seen on TV” exercise fad or join a gym with special adductor machines? Short answer: No.
Starting with anatomy, the adductors consists of eight muscles: Pectineus, gracilis, adductor longus, adductor brevis (superior and inferior), and adductor magnus (superior, middle, inferior). The adductor magnus group is the heaviest adductor muscle and one of the largest muscles of the body, second only to the gluteus maximus. As such, if one of your goals is fat loss, your workout should involve the adductors as their energy expenditure is extremely high.
The term adduction can mean, “to bring together.” Pull your arms apart and then clap -- that’s adduction. Thus, one of the functions of the adductors is to pull the legs towards the midline of the body in the frontal plane -- think, “ADD-uction.” They are also involved in rotating the upper thighs inward (hip internal rotation). In contrast, the abductors have the opposite function, moving the legs away from the midline of the body and creating hip external rotation.
From a performance standpoint, muscular weakness in the adductors, or imbalance between the adductors and abductors, can lead to groin injuries and injuries to the anterior cruciate ligament (ACL). Women are at higher risk than males of ACL injuries, so it’s critical for them to consider exercises to ensure these muscles are strong and have optimal structural balance. One simple test to determine structural balance would be the overhead squat. If the knees flare outward during the descent, the adductors could be weak; if the knees buckle inward, the abductors could be weak. However, consider that fallen arches (valgus feet) may also cause the knees to buckle.
In many sports, athletes simply do not like spending time in the weightroom. There are, however, exercises for the adductors than can be performed without any special equipment and performed on the field, after practice (which is best, as the muscles will be warm and less likely to become injured). Elastic tubing exercises are convenient and can be used, but there are many effective bodyweight-only exercises – both are often performed in aerobic fitness classes.
Before getting into the best ways to train your inner thighs, let’s look at the most popular methods.
First, there are the seated leg adduction machines you find in most major health clubs. Before going further, consider that for those suffering from certain orthopedic conditions, such as patella tendinitis, these machines can provide a way to work the adductors without aggravating the injury. Likewise, those with foot or ankle injuries, and perhaps even a broken leg, may be able to use these machines without discomfort. Another way to work these muscles is from a standing position using a cable crossover or multi-station pulley system. You would attach a low pulley to an ankle strap, and perform adduction such as by crossing the moving leg in front of the other.
One problem with adductor machine exercises is that the way resistance is applied may place considerable stress on the medial collateral ligament (MCL) of the knee, although those that allow the exercise to be performed with the knees bent to 90 degrees reduce this stress. Consider too that these machines start you from the weakest biomechanical position, encouraging you to jerk to get the resistance moving. This action could easily cause injury. This is not to suggest you should never perform these exercises, but that it might be best to focus on doing higher reps and not using maximal weights for the repetitions performed. Or, perhaps, use them as a warm-up for other, more joint-friendly adductor exercises.
One unique way to work the adductors is to modify specific exercises by forcing the adductor muscles to work harder. Examples include squeezing a medicine ball between the knees while performing leg presses or sit-ups. These variations increase the work of the adductor longus, but only in the peak-contracted position.
Another option is a lateral step-up on a box, such that you stand sideways to a box with one foot on the box, then step up. This version also requires you to start from a position of biomechanical weakness, but there is also an issue with balance, especially when holding a barbell across your shoulders. One way to improve your stability is to perform the exercise by holding the handle of a low pulley, such as those on a functional trainer or cable crossover, but it’s difficult to use a significant amount of weight with this variation to get a strength training effect.
A better option, and one that can be performed indoors or outdoors, is lateral sled pulling. For example, stand sideways to a sled, grasp the rope handle with one arm (the arm closest to the sled), and extend your arm. From here, step sideways with the leg furthest from the sled and bend your knee, then straighten that leg and pull your free leg back to the midline of the body. Repeat this sequenced for a specific number of steps, and increase the resistance by adding weight to the sled. There are many more variations of lateral sled drags, including crossover movements in which you cross one leg in front of the other as you pull the sled.
Two superior adductor exercises that start from a biomechanical strong position are the lateral lunge and the lateral lunge with a slider. With the second exercise, you drop straight down on one leg while the other one slides out to the side on a special disk designed to slide easily. This is a more stable version that the side lunge, which entails stepping sideways and then squatting down with that leg, then pushing back with that leg to the start. A barbell can be placed on your shoulders to increase the resistance on these exercises, or by holding a weight plate against the chest for beginners.
Three more practical and effective ways to safely strengthen the adductors are squats, leg presses, and deadlifts performed with a wide stance. For squats and leg presses (considering that the footplate is large enough), the position is slightly wider than shoulder-width; for deadlifts, this “sumo stance” can range from slightly wider than shoulder-width to nearly the distance of the inside weight plates. The feet are flared outward on all these lifts. These are extremely stable exercises and resistance can be increased in small increments, factors that increase their safety and enable you to train at a higher intensity. However, the range of motion is limited on these variations, so it’s a good idea to occasionally perform exercises such as lateral lunges to ensure complete development.
Regarding sets and reps, the adductors are a mixed muscle fiber type, so respond well to both higher and lower repetitions. One approach would be to use higher reps/lower sets (such as 3 x 12-15) for two weeks, then lower reps/higher sets (such as 4 x 4-6) for two weeks. Even lower reps can be performed for squats and deadlifts, including singles, but for other exercises that start from a weak position and work the muscles through a full range of motion, higher reps should be performed to avoid placing an excessive amount of tension at the start. Here is an example of how exercises could be structured:
Weeks 1-2, Side Step-up, 3 x 12-15, 2010, rest 60 seconds
Weeks 3-4, Wide Stance Squat, Barbell, 4 x 4-6, 4010, rest 240 seconds
Weeks 5-6, Lateral Sled Drag, 3 x 10-12 steps each leg, 1010, rest 120 seconds
Weeks 7-8, Sumo Deadlift, Barbell, 5 x 3-5, 30X0, rest 240 seconds
Certainly, there are many high-tech exercise machines that make our workouts more efficient and effective. Some of these machines focus on the adductors, but simple variations of many basic lower body exercises can be even more effective. So go ahead and squeeze your Thighmaster while watching TV and eating popcorn, but when it’s time to get serious about training your adductors and turn your mood ring black, pull some sleds and lift real weights!