Intro
When we discuss training the legs, it’s common for us to default to exclusively thinking about hams and quads. For some, we can throw the glutes in their too, but it’s typically an afterthought to consider the adductors. To help shed some light on the importance of training the adductors, consider the injury rate that adductor/groin tears occur. In a study published by (1), researchers analyzed hip and groin injuries across collegiate athletics from 2009-2014 and reported 1,984 hip/groin injuries. In total, adductor/groin tears accounted for ~25% of all injuries, which was the most frequent injury occurrence (1). It was also noted that most adductor/groin injuries occurred in sports that involve kicking, skating and sudden changes of speed or direction.
The adductor group is critical to performance, irrespective of sport. Even sports that aren’t frontal plane dominant need to be cognizant of the adductor group considering their roles in flexion and extension. Moreover, the adductors play a major role as synergists in a myriad of hip movements and in a sense, can be the underpinning to optimizing global hip function.
Let’s take a look at a practical example of adductor function to illustrate this.
As described in (2), during rapid or complex movements involving both legs, the adductor muscles are bilaterally and concurrently active while contributing to pelvic stability. For instance, consider the reciprocating and varying roles of the adductors required during a high kick. On the stance leg, we have terminal hip and knee extension while the adductors are isometrically adducting while managing a tremendous amount of torque. On the kick leg we go through essentially an entire ROM at both the hip and the knee, varying the role and contribution of the adductors throughout the kick action. But consider the roles in assisting both rapid flexion and extension, along with producing a tremendous amount of force.
Another common issue pertaining to the adductors is when quads and hams become overly dominant. When muscles aren’t used, or aren’t trained in this context, they shut down and begin to atrophy. When muscles shut down not only do they become vulnerable, but they destabilize the whole system, namely the hip joint. In this case, if we were to continue developing the hams and quads while persistently neglecting the adductors, the hams and quads will become overworked. At this point, not only are the adductors a vulnerability, but we’re now jeopardizing injury to the hams and quads as well.
Adductor/Abductor Relationship
The adductors are a rather peculiar muscle group, which include the adductor brevis, longus, and magnus, along with the pectineus, and gracilis. Their peculiarity lies in that they are able to adduct, internally rotate, flex, and extend the hip (2). The brevis and longus both contribute to flexion, while both heads of the magnus contribute to extension (3). Although this may seem counterintuitive, the same irregularity is true for the abductors as well. Primary abductors include all fibers of glute medius and minimus, and the TFL. However, based on the position of the hips/legs, the responsibility of these muscles can change.
For instance, when the hip is flexed beyond ~40°, the line of force for the adductors crosses the extensor side of the medial-lateral axis of rotation which provides them leverage allowing them to contribute to hip extension action (2). Moreover, when the hip is near terminal extension, the adductors are mechanically prepared to assist hip flexors as synergists (2). There is a nearly inherent triplanar demand placed on the adductor muscles, which in part may explain why groin strains and tears are such a common athletic injury.
A component of hip abductors that is very often overlooked in coaching is their role as internal rotators. This is particularly true when the hip is in flexion. Fundamentally, this doesn’t appear to be possible. However, the anterior fibers of the glute medius and minimus contribute to hip internal rotation, and in conjunction with the TFL, are capable of combining hip abduction and internal rotation torque at the hip (3). The primary point to take away here is that degree of hip flexion is extremely important for isolating specific muscles and muscular action in training. We can also use this for assessing injuries and movement restrictions. A common example is confusing a groin strain for a structural internal rotation deficit. By adjusting the athlete and placing them in positions of varying degrees of hip flexion, we can more adequately and accurately assess the issue.
Internal/External Rotator Relationship
The primary internal rotators include the iliacus, adductor brevis/longus, and the anterior fibers of the glute med. (2). I don’t want to make an overly generalized claim here, but just about every athlete I see has weak or underdeveloped internal rotators. Even the athletes that can passively move into full range of hip IR, most of those can’t actively utilize the muscles very well. The relationship here between internal and external rotators is very similar to the ones outlined above. One group gets compromised by being short and weak, the opposite group being lengthened and weak. Each of those then possessing their own cascade effects that disrupts function elsewhere at the hips.
What’s particularly important to note with the internal/external rotator group is (again) how their roles change based on degrees of flexion or extension. I’ve already alluded to this a bit, but the role or responsibility of these muscles’ changes based on the position we work from. This really illustrates the importance of utilizing a multitude of stances, positions, and movement planes in training. For instance, working out of the split position puts one hip in flexion and the other in extension. By doing so, we are fundamentally changing the role of the adductors on each leg, which then changes the functional role of the glutes and other muscles crossing the hip joint. Additionally, working from different depths in the split position can have beneficial effects as well. The deeper into flexion we go, the more demand we place on the internal rotators to work as hip/pelvic stabilizers to maintain proper pelvic alignment (3). The point here is really just knowing how to apply your anatomy, and how to position an athlete that may have a specific demand or weakness.
Assessing the Adductors
Static assessment for the adductors is very straightforward. I use the manual muscle testing protocols outlined in NKT to isolate and determine individual strength of each primary adductor muscle. In addition to the manual muscle testing, I will also assess the tissues general extensibility (or ‘flexibility’) in various positions. As for dynamic assessment, I will mostly rely on the SL Hinge, split squat or lunge, and bilateral squat to get an idea of how the adductors look functionally. Let’s breakdown some common issues I see with these.
What I’m looking for first on the SL hinge is any presence of weak glute med/min on the stance leg (Trendelenburg sing). If the athlete has weak or underdeveloped abductors, then we can make a safe assumption the adductor group will be compromised as well. In this case, the adductors would likely be short/weak and compromised in frontal plane actions. Next, looking at the swing leg, we will often see athletes who either cross their midline or kicks the toe out and away from the body (videos shown above).
This could be indicative of either chronically shortened/weakened (crossing midline) or chronically lengthened/weakened (toeing out) adductors. Additionally, with the stance leg, I’m looking to see if there is any presence of excessive anterior or posterior pelvic tilt, or excessive overpronation at the foot. In either case, the adductor group can be compromised. Considering the role the adductors play in hip flexion and extension, being chronically shortened or lengthened can have disruptive effects on movement. For example, excessive anterior pelvic tilt disrupts the hips ability to work in flexion. The adductors could be a part of this limitation, especially in deeper ranges of flexion and/or extension.
On our second screening, the split squat, there are two major things to look for and both are pretty easy to detect. The first being medial or lateral tracking of the knee on the back leg. When the back knee collapses medially, it could be indicative of a chronically short/tight adductor pulling the knee into the midline as we go into deeper ranges of hip extension. As for lateral tracking, while this could be glute med/min. being short/tight, it could also be a sign of simply a weak adductor unable to keep the knee in good position.
As for the front leg, we are really just looking for any presence of medial or valgus knee collapse. In this case, we know that dynamic knee valgus has been correlated to weak lateral glute muscles. But I would also argue that hypertonic, short/tight adductors could also be at play here.
One more thing to consider with the split squat is the distance between the feet and the width of that stance. I will cue this by telling the athlete to “stay on train tracks, not a balance beam”. Remember, we want as much of our training to be reflective of sport or demands of duty. Think about trying to run a sprint with your feet striking in front of one another… not too effective right? Anyhow, athletes with mechanical disruption at the hips, including chronically tight/short adductors, will often favor a narrower distance between feet on split stance work. It’s important that we correct this and at the very least keep them at roughly hip-width apart. I would rather have an athlete with appropriate foot position and reduced ROM than work deeper ROM with a poor foundation 10/10 times.
Bilateral Squat
The bilateral squat is sort of like the final exam. We’ve looked at the hips/adductors in isolated movements, now it’s time to see how everything functions altogether. Major points on the bilateral squat are really going to be redundant from the items above. The consequences of dynamic valgus pattern on bilateral squatting has been well documented. And again, although dynamic knee valgus (particularly in a bilateral squat) is typically linked to weak glute med/min., we have already discussed how dysfunctions are never singular. Weak glutes are going to affect the adductors in some capacity as well.
What I also look for in the bilateral squat is the infamous “butt wink” pattern, or excessive posterior pelvic tilt in the bottom of the squat. I’m not going to get into the never-ending theories surrounding butt wink, however, I do think this could be a sign of overly tight adductors in some cases. Conversely, excessive anterior pelvic tilt at the top of the squat can be indicative of some adductor disruption.
The caveat to all the screening measures is that this doesn’t indict the athlete one way or the other. This doesn’t inherently exclude the athlete from any movements or training intensity. All that we are doing is simply getting a map of how they move. Where they are strong vs. where they may be vulnerable. What specific positions and movements we should emphasize in training, and as it pertains to the adductors- what we need to adjust in training to improve strength and function. Without a clear and legitimate diagnosis, don’t look too much into assessment findings. This is all just for you to have a thorough understanding of what you’re working with.
Training the Adductors
Training the adductors in the frontal plane (i.e. into adduction) is fairly common practice, at least in most (good) facilities. Consider exercises like the adductor or Copenhagen Plank or Lateral Lunges. Items such as these should be fairly routine exercise selections and are certainly a good foundation.
What I’ve found a lot of success with when targeting the adductors, is simply varying the stance or position you have your athlete working from. For example, consider an athlete who has short/tight adductors. I’ll have this athlete perform a ton of work out of the sumo position to emphasize eccentric/isometric loading on the adductors. Everything from DB goblet squats, MB atlas hinge, and even DB OH Pressing. For coaching the sumo position, I like to emphasize squeezing the ground with the feet while favoring supination/external rotation, drive the knees out over pinky toes, and “squeeze a grapefruit” between the upper thighs. Using a variety of stances and positions is crucial for effective training, but it can be meaningless without effective cueing.
Obviously, you know we’re going to talk about SL stance work. Moreover, I would encourage the bulk of your SL work be performed without shoes. Interaction between the feet and the ground is critical for specific and optimal hip function. Consider how the shoe acts as not only a brace for stabilizing the foot, but also how it blunts or interferes with proprioceptive input. We want the athlete to be able to feel, sense, and respond to subtle changes in the foot pressure as it shifts from pronating to supinating. In any event, recognizing the inherent demand for triplanar stability required when working out of the SL stance, the adductors are obviously going to be a major player pretty much irrespective of movement.
Most frequently I will work hinge variations, including SL RDL variations, SL hinge or good morning variations, and SL squat patterns. But with the adductors specifically, we want to start to add in elements of rotation where prudent. A great one I’ve stolen directly from Vern on this is the SL Airplane w/ rotation. With this variation, we are taking the athlete into controlled pelvic rotation on top a fixed femur, while particularly stressing the internal rotators and adductors eccentrically. I like the uncommon plane or path of motion on this one as an added bonus. A really solid option as a warm-up/movement prep or accessory movement.
Consider the mechanism of most sport actions involving cutting or change of direction, not even necessarily pertaining to injury mechanism, but even just in general. Most of these actions occur by way of pelvic movement atop a fixed femur. Adding to the fact that the majority of these actions occur under tremendous velocities and torques. Nevertheless, various rotational hinge patterns, chop variations, and rotational/anti-rotational patterns are all good options for establishing foundational stability and introducing angular movements. As the athlete continues to develop a solid foundation, higher velocity movements such as landmine and med ball variations to emphasize the velocity and torque aspects.
Strengthening the adductors isometrically is also key. As we already touched on, Copenhagen plank variations are great for foundational frontal plane strength. Building from there, though, we want to again think in more natural positions. This can again be achieved predominantly through a combination of SL and rotational/anti-rotational modalities. Think about something like a SL Palloff press for example. This is a great foundational strength piece for the adductors because we are challenging them not only in the frontal plane as stabilizers, but now we’re also challenging them to resist being pulled into external rotation. The bonus with this exercise is simply by switching which leg is the stance leg, we will create an emphasis on the external rotators by forcing them to resist being pulled into internal rotation.
We can also challenge the adductors in deeper ranges of hip flexion. By going deeper into flexion, we are going to now work more of the adductor brevis and longus which are the two that contribute to flexion. For this, I will usually start with something like a banded hip flexion w/ internal rotation emphasis. I like this particularly because it simulates (loosely) a position we would run or sprint from. On a more foundational level, variations like a split squat w/ adduction bias are great options for warm-up or intraset work.
The last training item I wanted to address is simply attacking angles. What we want to look at here is essentially bisecting conventional cardinal planes of motion. Two of my favorite movements for introducing this concept are Curtsy lunges and crossover step-ups. With these movements, we are working at closer to 45° angles, rather than purely conventional frontal or sagittal plane. The ‘combination’ of planes, challenges the adductors in multiple ways, including their abilities to manage internal and external torques. I should also note, where above we’re emphasizing stability with the chops and Palloff presses noted above, here we are emphasizing foundational strength. These movements should be loaded up to tolerance.
We can also create a slight bias for internal or external rotation in conventional movements. Using something simple like a split squat, we can slightly adjust the back leg in order to create more demand on the adductors. These minor tweaks can create a major change in outcome, especially for athletes with specific deficiencies.
Bringing it All Together
-Primary adductors include adductor brevis, longus, and magnus, along with the pectineus, and gracilis.
-Secondary adductors include posterior fibers of glute max, biceps femoris, quadratus femoris, and obturator externus.
-Adductors contribute to a myriad of hip movements, include assisting in flexion, extension, and internal rotation.
-Groin/adductor tears are the most commonly injured hip muscle across collegiate sports. It is widely believed that their role in multiple planes of motion may have something to do with the high frequency of injury.
-As such, emphasizing adductors in planes outside of simple frontal plane adduction is critical for optimal health and performance.
-Use a variety of stances, positions, angles, and ranges of motion to work from.
-Include a sufficient amount of SL work to optimize adductor function. Perform the majority of your SL work without shoes.
-Be sure to train adductors by including specific emphasis on eccentric and isometric loading; no different than other major muscle group.
Sources
1.) Kerbel YE, Smith CM, Prodromo JP, Nzeogu MI, Mulcahey MK. Epidemiology of Hip and Groin Injuries in Collegiate Athletes in the United States. Orthop J Sports Med. 2018;6(5):2325967118771676. Published 2018 May 11. doi:10.1177/2325967118771676
2.) Neumann, DA. Kinesiology of the Hip: A Focus on Muscular Actions. J Orthop Sports Phys Ther (2010). Doi: 10.2519/jospt.2010.3025
3.) Pereira, GR, Leporace, G, Chagas, DV, Furtado, LFL, Praxedes, J, and Batista, LA. Influence of hip external rotation on hip adductor and rectus femoris myoelectric activity during a dynamic parallel squat. J Strength Cond Res 24(10): 2749–2754, 2010.