The correction of valgus knee fault in squatting, focusing on the common ‘knees out’ cue.

Within the dominion of Strength and Conditioning, the most beneficial exercises are sought to maximise the physiological and morphological adaptations that occur due to load and stresses placed upon the system. A contentious issue is that of optimal movement and injury prevention. The purpose of this paper is to discuss the valgus knee (VK) fault in squatting and the use of the “knees out” cue in its correction.

The determination of a VK fault is the degree at which the Q angle is set, the Q angle is the angle formed by a vertical line taken from the ASIS through the patella, and a further line from the central patella region to the tibial tubercle, as demonstrated in Figure 1. (Atanda et al., 2009)

Figure 1. Representation of a valgus knee (Atanda et al., 2009, p. 427)

Due to the nature of gendered structural differences, the recommended or ‘ideal’ angles differ between genders. In women, less than 22 degrees with the knee in extension is the desired range and with the knee at a flexed position of 90 degrees, like that of a squat position, less than 9 degrees. In men, in extension less than 18 degrees and less than 8 degrees with the knee in the squat position at 90 degrees of flexion. A typical Q angle is 12 degrees for men and 17 degrees for women (Emami et al., 2007). The reason to be aware of the Q-angle in squatting is having the knees collapse into a valgus position is generally regarded as sub optimal technique, due to the increased possibility of injury. (Myer et al., 2014)

There is contention within the VK role in knee injuries, the overriding theme within the literature is that a VK may be a factor within the development of ACL injuries. This corrleates with the higher incidents of ACL injuries in female populations (Ireland, 2016) alongside the higher rates of VK. VK is displayed in a high proportion of non-contact ACL injuries, but the presence of a planted foot with external tibial rotation during and deceleration is also frequent (Boden et al., 2000; Krosshaug et al., 2007). Therefore the attributation of ACL injuries to just VK is unlikely. Conversely the premise that isolated ACL injuries are to be attributed to knee abduction was disputed with the argument that the ACL is not a major load bearing structure when the knee is in a valgus position (Yu & Garrett, 2007). Although clinical and cadaver studies, including the use of imaging and diagnostic information, intermate that VK is probably present within ACL injuries, due to the presence of bone bruising to the lateral femoral condyle or posterolateral portions of the tibial plateau, found in 4/5 cases (Kaplan et al., 1992; Viskontas et al., 2008). Therefore, it appears the presence of VK in itself in an isolated sagittal plane movement has little evidence to support its attibutation to ACL injuries, however VK with the addition of rotation and change of direction is a mixture greating much greater likelihood of ACL tears. Thus it would be deemed appropriate to avoid a knee valgus where possible to reduce the risk of injury.

To highlight the impact of varying anthropometrics the adductor magnus plays an important role in hip extension during the squat, producing on average, more than 50% of the net hip extension moment (Vigotsky & Bryanton, 2016). Thus, this force produced at adductor magnus could be a key factor, as a strong contraction alongside the production of hip extension will also produce an inward movement of the femur, especially in those with longer femurs and a relatively stronger adductor magnus.

Upon correcting the knee valgus especially in the squatting exercise, a lot of practitioners are quick to move towards maximising the gluteus maximus, as this provides a level of external rotation and abduction of the femur alongside stabilising the pelvis, especially in a single-leg standing position (Buckthorpe et al., 2019). Therefore, logic would dictate that stronger gluteus maximus would present with a more capable capacity to resist adduction of the femur and in turn reduce the possibilities of knee valgus occurring, subsequently reducing the risk of ACL injuries becoming associated with this movement pattern (Nessler et al., 2017). Contrary to this, research has also presented findings of no significant difference in gluteus maximus activation through EMG between sexes when performing a single leg drop landing, although there was a significant difference in knee valgus (Russell et al., 2006), presenting the idea the gluteus maximus may not be as much of a driving force behind preventing knee valgus as first postulated. Furthermore, a large amount of the research in assessing squatting kinematics and interventions upon correction of a VK in squatting appears to have a couple of issues within the testing, one being the standardisation of the position (Bell et al., 2013), two being that intervention studies use submaximal loads and athletes new to squatting. Therefore, there is less chance for technique breakdown upon re-test, due to the submaximal nature of the test and the possibility that improvement in kinematics is due to practising and rehearsal of the squat movement, as opposed to the interventions placed upon it.

A coaches role is to maximise athletic potential and reduce the risk of injury. Therefore if a VK is observed when squatting it is desirable for the coach/athlete to attempt to correct this movement pattern, thus allowing for the achievement of more desired and ‘optimal’ positions through training and competition. A common approach to the knee valgus issue is with relevant cueing. Cueing is the stimulation of a change or adaption to a movement through an internal or external stimulus that hints or indicates movement or behaviour (Atkinson et al., 2018). External cueing is relatively simple, using relevant imagery or direct short instructions to exhibit the desired response, or more simply put focused on the outcome or appearance of the movement; conversely internal cueing is that which is focused upon the body and how it is moving and the feeling of the movement (Winkelman, 2018; Wulf et al., 1998). The external cueing methodology seems to have greater outcomes in performance as the body can self-organise to attain the highest level of outcome possible; Wulf et al.,(Wulf & al, n.d.) describes that external focus allows for the adoption of relatively automatic control processes, thus performance is more effective and/or efficient. The internal cues appear to be more useful in controlling the body and position, but create a level of restriction to performance as there appears to be an attempt to constrain or control the motor system, not inherently bad, but could put a ceiling upon performance (Stoate, 2011).

When ascertaining the predominant methods of movement correction for a VK a google search of “knees out cue” returns 17,500,000 results, therefore, quite possibly a widely used method for the attempted correction of a VK. The attempt to alter a VK via the aforementioned “knees out” vocal cue, which is itself a harmless iteration of an intrinsic cue and as alluded to earlier, requires the athlete/lifter to spend more time engaging and focussing on the positions within the body, and therefore not executing maximal power. Herein lies the possible issue of practising the optimal position with only ever being able to utilise sub-maximal intensity due to the cueing, and thusly remaining within the cognitive and associative stages of learning, as opposed to achieving automotive stages of learning (Fitts & Posner, 1967) required to handle the heavier loads essential to eleicit the training response desired. Therefore, when the situation arises to produce maximal force or power, the body will default to its automatic response to the stimulus (Neumann, 2019).

A further issue with the “knees out” cue is the fact it appears to breed an impassive generic attitude towards coaching and has become a somewhat blanket statement, a one size fits all approach to aiding athletes within the squat. As previously mentioned, the different stages of learning alongside training age and anthropometric differences may make this an ineffective and possibly detrimental cue to performance. The mass media opinion is that all VK are bad, however, many of the world’s top lifters/athletes display a VK, particularly when attempting a max weight, possibly due to the afformentioned strong activation of adductor magnus. The blanket use of this cueing mechanism without the discernment between a VK fault and a valgus moment, in which an athletes knees may move toward the midline but does not cross it, appears as an issue. However, this is an issue with the coaching practice opposed to the cue in itself. Ideally the use of a strong external cue to create an optimal joint movement pattern, while not attempting to cause the athlete to fight against that natural anthropometry, and therefore, display the highest-level performance and outcome. While the reduction of a VK is desired to lessen the possible chance of injury there may be certain times where it is more acceptable than others. For example, It can be contextually appropriate to have extra degrees of freedom within movement paradigms to achieve a higher level of performance with the increased risk of injury, due to the possibilities of winning trophies/championships/contracts etc.

To surmise the VK, while not ideal it needs to be assessed on a case by case basis and as an alternative to casting out a wide “knees out” cue, the art of coaching may be to find the external cue that allows the athlete to display best performance in the squat, while minimising the cues impact of performance. The ability to match the correct variation of the squat so that it manipulates the capacity to be worked and at the intensity required to elicit the desired adaptions, could also be a more streamlined approach to the improvement of performance, as opposed to fighting the battle of squatting in a certain manner without reason.

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