Understanding the physiological and biomechanical demands of a sport and the current ability of an athlete to meet these demands is of paramount importance when both preparing for competition and providing late stage rehabilitation following injury.1 In order to evaluate these demands a needs analysis of the sport and athlete is undertaken, this will consist of varying elements depending on the sport in question. It will often include, for example, a time motion analysis, a profile of energy systems, strength diagnostics, sport biomechanics, and research into injury epidemiology and aetiology.2 3
An essential component of the athlete-specific needs analysis is a movement screen, commonly consisting of a battery of assessments with the aim of determining potential injury sites, movement restrictions, and kinetic chain dysfunctions from a global perspective. The presence of dysfunction and restrictions will force the body to create compensatory movement strategies (CMS) in order to retain its ability to carry out movement tasks, These CMS are often kinesiopathologic,4 5 due to suboptimal load transference throughout the system and causation of undue mechanical stress to bodily structures. As such, it is important for a strength coach/sport rehabilitator to perform movement screens since it is far more effective and efficient to be proactive in addressing dysfunctions and restrictions rather than being reactive to injury when it occurs.
Movement screens are generally based around functional movements rather than isolated motion on a plinth, this allows the strength coach/sports rehabilitator to determine any CMS the athlete uses when performing sport-specific tasks. This is highly important during initial screening, but maybe more so in late stage rehabilitation as it must be ensured that the athlete is sufficiently robust and mechanically sound to avoid re-injury. This is particularly evident as previous injury has been demonstrated as the most reliable predictor of re-injury.6
Numerous function-based screens have been developed and demonstrated to be effective, some of these include; the Y Balance,7 Performance Matrix,5 and Functional Movement Screen (FMS).1 All of these screening systems have their individual merits, however currently the FMS is the most well-known and used. The aim of this paper is firstly to discuss, critique and provide possible modifications for the FMS. Secondly an evaluation of an athlete’s deep overhead squat (OHS) will be provided, whereby restrictions will be highlighted along with potential interventions to improve their performance of the movement.
The FMS1 consists of a battery of seven fundamental movements which challenge mobility, stability, and motor control (see Cook1 and Cook8 for full details of the movements involved). These movements theoretically form the foundation of all other sport-specific patterns.9 The premise of the FMS is that athletes may be predisposed to injury and suboptimal performance if asymmetries, weaknesses, limitations or imbalances are present in any of these movements.1 10 This subsequently alerts strength coaches/sports rehabilitators to these issues and permits them to carry out diagnostic testing on the athlete concerned.
To determine movement competency each movement is scored on a zero to three ordinal scale. A score of zero signifies that pain was experienced in the movement. A score of one indicates an inability to fully complete the movement. A score of two signifies movement completion but with a degree of compensation. A score of three is given if optimal performance is demonstrated. Five of the tests are given a separate score for the left and right side of the body to account for asymmetries, although only the lower of the two is taken for analysis. The sum of these scores forms a composite score of between zero and 21.
The FMS has been demonstrated to have an acceptable ability to predict injury in male military personnel,11 male athletes,10 and female athletes12 when the composite score is <14 (determined via use of a receiver-operator characteristic curve.13 In fact findings from Kiesel et al10 stated that football players were as much as 12 times more likely to be injured with a score below this cut-off point. There are, however, issues with 14 being a cut off score. One argument is that it is possible to score more than 14 even with asymmetries in all of the two-sided tests. Asymmetries are suggested to be a risk factor for injury by a number of authors.1 14-15 Yet little evidence exists to support this suggestion. In a study by O’Connor et al11 no statistical evidence supported asymmetry as a risk factor for injury in military personnel. Additionally it is possible, as in the case of stroke victims, amputees, and cerebral palsy patients, to function and live pain-free with compensations and asymmetries. On the contrary, an athlete in a lower-limb dominant sport may receive a composite score of 14 but still have scored mostly threes in the lower-limb movements. This raises the question of whether this athlete is truly at risk of injury.
Research has additionally critiqued the FMS composite score as a whole, stating that it lacks internal consistency and does not function as a unidimensional construct,16 thus changes to the scoring system have been.17-18 In one study18 it was suggested an objective motion capture system could be used. The researchers compared manual grading (standard subjective FMS criteria) to an objective grading criterion using video and kinematic thresholds related to each FMS grading criteria. The rationale for this research was that the FMS scoring system assumes the tester can adequately distinguish the mechanics relevant to each of the grading criteria in order to grade them accurately. The results of this study showed discrepancies between the manual grading and objective grading methods, highlighting that manual grading may not be a valid method. Butler et al17 also proposes changes, suggesting a 100-point grading scale. The researchers theorise that this will promote greater precision (higher inter-rater reliability) and provide more distinction between scores along with offering more detail as to when movement issues occur.
Despite the aforementioned scoring system faults the FMS has been shown to have high levels of inter- and intra-rater reliability19–21 And although content validity, construct validity, face validity, and sensitivity are deemed to be suboptimal, its specificity and injury prediction abilities are regarded as strengths.18 20
Within the suboptimal elements, lack of content validity may be an issue. This presents itself in the fact that the FMS only tests low load/low threshold movement strategies, whereas in sport the majority of tasks are high load/high threshold (different neural pathways). Frost et al22 looked at the influence of load and speed on five different foundational movement patterns and found that the subjects adapted their movement strategy as a response to heightened task demand. A screen should be a comprehensive, global approach to determine sport specific ability. A lack of high load movements in the FMS prevents it from fully achieving this aim. To improve this aspect of the FMS it would be advisable to borrow from the Performance Matrix method5 which utilises screen for both low load/motor control and high load/strength and speed deficits to identify problems.
The OHS is a commonly used screening tool due to its ability to test global mobility, trunk stability, control of posture, and overall total body mechanics. As a triple flexion/extension movement pattern, the ability to perform a bilateral squat has application to numerous physical activities. In the OHS, as per FMS criteria, an ideal technical model would include the points outlined in Figure 1 along with the ability to descend and ascend in a stable and controlled manner and maintain stability whilst in the bottom position.
Figure 2 was taken from the video provided and demonstrates an athlete’s ability to perform an OHS as per the FMS protocol. When comparing the screenshots in Figure 2 to the technical model in Figure 1 it is apparent that the athlete has a number of limitations in their performance of this movement. In the sagittal plane there is an excessive anterior trunk lean, an inability to break parallel (hip crease below knee level) in the bottom position, and a noticeable lack of dorsi-flexion. In the frontal plane the athlete demonstrates uncontrolled motion manifesting as a weight shift onto the right side, this is also apparent due to the angulation of the dowel held overhead. Due to these dysfunctions, the athlete would have scored a one on the (albeit flawed) FMS scoring criteria.
If an athlete scores a one on the FMS OHS they are permitted to attempt the movement with a two inch heel lift. Figure 3 shows the effect of this on the athletes’ performance. Noticeable improvements in depth, trunk angle and movement control are visible, which suggests that a lack of closed kinetic chain ankle dorsi-flexion is a limiting factor for this athlete. This athlete would now score a two on the FMS scoring criteria.
The ability to dorsi-flex the ankle has been demonstrated as essential when performing the OHS.23 To complete a full OHS with the foot in full contact with a flat surface evidence has demonstrated that 39 ± 6° of dorsi-flexion24 is required. Without ankle dorsi-flexion this athlete will likely be predisposed to injuries such as Achilles tendinopathies, anterior talofibular ligament (ATFL) sprains, hamstring strains, and flexion-type lumbar spine injury. These injuries may occur as the body will compensate for the lack of ankle dorsi-flexion by prolonging or increasing the velocity of pronation (to allow dorsi-flexion to occur at the mid-foot) which has adverse effects further up the kinematic chain. Decreased ankle dorsi-flexion may also cause inhibition of the peroneus longus muscle (amongst others); this muscle is required to decelerate ankle inversion (part of the mechanism for ATFL injury). If the body is unable to compensate through the foot complex, motion may come from increased hip flexion, increasing spinal loading during high load tasks. In addition to this, if a joint can not feel motion (due to restriction) mechanoreceptor function will be compromised, preventing afferent signals travelling to the central nervous system.
This athlete has previously had treatment on the contractile, non-contractile and neural tissues surrounding the ankle in order to improve dorsi-flexion range of motion (ROM), however these had proven to be ineffective. Therefore in order to address this restriction it would be prudent to now address the arthrokinematics of the talocrural joint.25 Reductions in dorsi-flexion ROM is linked to an inability of the talus to posteriorly glide on the tibia,26 potentially due to an anterior positional fault of the talus due to previous lateral ankle ligament injury.27
Mulligan28 29 suggests the use of mobilisations with movement (MWM) for individuals with this articular positional fault. These techniques have been demonstrated to cause a significant increase in ankle dorsiflexion ROM in 60 healthy subjects in functional tasks.30 An MWM for ankle dorsiflexion will involve a continuous passive mobilisation whilst performing full ROM active dorsi-flexion movements; these can be carried out either weight bearing or non-weight bearing.
A weight-bearing (half-kneeling) MWM was used as an intervention for this athlete. Prior to the mobilisations the athletes’ ankle dorsi-flexion range was measured objectively using the weight-bearing lunge test (WBLT)31 (Figure 4), this was important in order to determine if the MWMs were having an effect. If the WBLT score did not improve it would have been evident that the restriction may not have been articular in nature. Three sets of 15 repetitions (approximately 60 seconds) were performed on each ankle at a sustained and controlled pace. Upon re-doing the WBLT significant improvements were noticed in ankle dorsi-flexion ROM. This new ROM was then tested globally in the OHS, where improvement in squat depth and trunk angle were observed (similar to when using the heel lift), indicating that the MWMs were effective as an intervention. In light of this, the athlete was instructed on how to perform a self-mobilisation reported to have the same effect26 (Figure 5).
This paper has highlighted the importance of movement screening in athletic populations. A movement screen is comprised of battery of movements with the aim of detecting movement faults, which then enables strength coaches/sport rehabilitators to retrain these faults to prevent injury/re-injury. It is important to understand that there is no ‘one size fits all’ screen, as every sport involves different movement patterns and has different injury sites, thus it is appropriate forstrength coaches/sport rehabilitators to create their own. Every test, movement, exercise, or performance therefore can be used as an assessment. A number of screens have been suggested (such as the FMS) however these ‘pre-packaged’ screens commonly have flaws which can impact their application to clinical practice. These include limitations in scoring techniques, movement context (high vs low load) and sensitivity. An analysis of an athlete’s OHS was provided; optimal performance of this movement indicates good global mobility trunk stability, control of posture, and overall total body mechanics, which demonstrates good athletic performance potential. This athlete showed compensations when performing the movement, which upon investigation were due to a lack of ankle dorsi-flexion. Leaving this unaddressed could predispose the athlete to injury (ankle dorsi-flexion is a common probable suspect for injury). After a treatment of MWMs the athlete improved dorsi-flexion ROM and overall OHS performance. It may therefore be appropriate to recommend that this athlete (and others who lack dorsi-flexion) incorporate self-mobilisation of the ankle into their training regimes in order to enhance athletic performance and reduce the risk of injury.
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- Kiesel K, Plisky PJ, Voight ML. Can Serious Injury in Professional Football be Predicted by a Preseason Functional Movement Screen? N Am J Sports Phys Ther 2007;2:147–58.
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- Kasuyama T, Sakamoto M, Nakazawa R. Ankle Joint Dorsiflexion Measurement Using the Deep Squatting Posture. J Phys Ther Sci 2009;21:195–9.
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- Cosby NL, Koroch M, Grindstaff TL, Parente W, Hertel J. Immediate effects of anterior to posterior talocrural joint mobilizations following acute lateral ankle sprain. J Man Manip Ther 2011;19:76–83.
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