Anyerly

the kinaesthetic mechanisms within the

muscles are not sufficiently trained to the correct motor patterning of the movement, and the athlete is not aware that he or she is adopting a maladaptive position. Simply increasing the athlete’s awareness prevents the athlete from learning a compromised movement pattern. The coach should ensure that the athlete can tilt the pelvis and distinguish between hip and lumbar spine actions in an unloaded situation before correcting this during the squat. The athlete’s knees should track along the line of the second toe. A common fault seen during the descent phase of the movement is that the athlete brings the knees inwards into a valgus position, which significantly increases the risk of collapsing inwards and injuring the knee ligaments. This inwards movement of the knees may indicate a weakness in the hip abductors. Alternatively, the athlete may be exerting pressure through the inside of the foot (the instep) rather than through the entire foot. If this is a motor control issue, strategies to overcome this problem include actively encouraging the athlete to push the knees outwards during the descent and reinforcing a ‘rip the heels sideways’ action (increased glu- teal action encourages external rotation of the hip). Specific remedial gluteal strengthening exercises are introduced later in this chapter.

At the base of the movement the weight should be distributed towards the heels so that the foot remains flat on the floor; the weight moves towards the heels from the midfoot as the athlete descends. The relationship between foot position and weight distribution is important. If the athlete’s centre of mass remains directly above the midpoint of the foot (facilitated by an upright trunk position), weight distribution through the foot will be correct. But if the trunk leans forward either through excessive hip flexion or thoracic flexion during the descent or in the bottom position, the weight will be distributed towards the front of the foot. This forward lean often causes the athlete’s heels to leave the floor at the base of the squat (i.e., heel raise is the symptom; trunk lean is the cause).

Understanding an athlete’s anatomy is par- amount in analysing squatting movement. Remember that this is exactly what movement

analysis or screening is about—understanding what the athlete does in key movements and why so that corrections or reinforcements can be planned and delivered.

Although the focus of the movement analy- sis is on the actions of the hip, knee and ankle in the sagittal plane, the hip movement in the transverse plane is also important during the squat. Using the lateral rotator muscles of the hip (piriformis, gemellus superior, obturator internus, gemellus inferior, quadratus femo- ris, obturator externus and the lower fibres of the gluteus maximus), the athlete can rotate the femur at the articulation with the pelvis. This rotation allows the hips to move forwards slightly, which moves the centre of mass back within the base of support, allowing the athlete to maintain a stable and balanced position. This action can be prompted by asking the athlete to push out sideways through the heels whilst descending through the squat. This prompt is also useful in correcting an athlete who demonstrates a knee valgus (inward rotation of the femur) during movement descent.

Using a scoring system such as the one used for the squat encourages two things. First, the checklist (figure 6.10) provides the practitioner with a series of technical points to guide the observation process during the movement. A scoring system is especially important when the practitioner is developing experience in movement observation. The sliding scale also enables the practitioner to record what is wrong with the movement, providing a basis for

constructive and corrective intervention and a permanent record that, in review, will enable the recording of technical progression. The extent to which the identified movement may be problematic can also be determined using this method. For example, if the athlete displays a slight anterior pelvic tilt during descent, the mark on the scale may be closer to the midline than if the athlete has a pronounced anterior pelvic tilt, in which case the mark on the scale will be further to the left end of the scale.

Looking at the interaction between the technique variables as well as each point in isolation is important. For example, if the athlete is able to move the hip below parallel only with an anterior pelvic tilt or forward trunk lean, this issue should be identified by cross-reference to the information recorded on the scales. The practitioner would observe the athlete move until, for example, the athlete could not maintain a neutral pelvic position (normal lumbar curvature), and then record the depth at which this occurs.

Some criticize such sliding scales as being subjective rather than quantitative. But even movement screening tests that record numbers often rely on the practitioner’s ability to make qualitative assessments of the movement and then attribute numbers to the observation. This practice is arguably no less subjective and provides little in the way of a permanent record of exactly what the observations were.

Some movement assessment screens use a sliding scale of major problem or deviation,

E5649/Brewer/fig 06.10/550936/HR/R1

Squat

Movement initiation: Trunk:

Head:

Head faces forward during descent Neck flexes Neck stays neutral Neck extends Knees Simultaneous hip and knee flexion Back hip flexion Forward lean Upright Thoracic Anterior pelvic tilt Neutral pelvis Posterior pelvic tilt Hips below knees Hips level with knees Hips above knees

Lumbar-pelvic region: Depth:

Knee alignment:

Weight distribution in bottom of squat:

Valgus Over second toe Varus Toes Mid-foot Towards heels

minor problem or deviation and normal or no problem. This scale enables the practitioner to record observations in relation to his or her perception of how problematic an observed movement dysfunction appears to be. For example, studies have found that tennis play- ers had on average 43.8 degrees of internal rotation and 89.1 degrees of external rotation on the racket arm compared with 60.8 degrees of internal rotation and 81.2 degrees of exter- nal rotation on the nondominant hand as a function of their play and practices.6 _Unsur-

prisingly, similar asymmetrical patterns have been found in other activities such as baseball pitching.7 _{In elite rugby players, limited inter-}

nal ranges of movement (less than 60 degrees) have been linked to increased risk of shoulder injuries, as has reduced eccentric strength in internal rotation activities.4

Scoring systems based on deterministic analyses of each symptom of a movement dys- function (such as the one used for the squat) are highly preferable to systems that allocate a single numerical score to an exercise within a screening battery. For example, Cook3 _suggests

five conditions for the in-line lunge movement that must be met if the exercise is to score 5/5:

• The feet must remain in contact with the taped line on the floor.

• The heel of the front foot must remain in contact with the floor.

• The back knee touches the floor immedi- ately behind the front knee.

• The trunk does not flex forward at the hip or thoracic spine.

• Balance is maintained (the dowel does not dip).

One point is lost for every one of the condi- tions that is not met. Note, however, that for this scoring to be informative to programme development, it has to be accompanied by an observational record noting what caused the score. For example, let’s imagine that the ath- lete’s feet move off the tape as he or she loses balance when the heels come off the floor, which in all probability will also cause the dowel to tip (so the score is 2). If only the num- bers are recorded without any observational notes, the score may prompt an intervention

of balance training and lower-limb mobility work. Subsequent retesting may score a 3 if the athlete’s heels come off the floor as the trunk flexes forward and the centre of mass moves forward. The score looks to have improved slightly over time and the symptoms of move- ment dysfunction are similar, yet the causes in each instant are considerably different. A change in score can indicate progress in overall athletic development, but it doesn’t necessarily identify a change in the athlete’s mechanical control.

Although less common than practitioners realize, another reason for the athlete’s heels coming off the floor in this position is poor ankle mobility, which would be highlighted by a targeted follow-up test. This circumstance is another reason to use generic screening tools, because they often highlight areas of postural deficiency that require further inves- tigation through more specific tests that may either quantify or rule in or out the need for specific interventions. For example, a simple follow-up test can identify whether reduced ankle mobility is what causes the athlete to lose position in the lunge. As figure 6.11 shows, if the athlete puts a foot onto a raised step (20

Figure 6.11 Ankle mobility test. The athlete

places a foot on a raised step and pushes the knee forward over the toe. If the knee can move in front of the toes while the weight remains through the athlete’s heel, the athlete’s ankle mobility typically will not limit squatting actions.

to 40 centimetres), keeps the foot flat and can push the knee forward of the toes whilst main- taining heel contact with the flat surface, ankle mobility isn’t a primary focus for intervention.

But if the athlete cannot do this without the heel coming off the step, ankle mobility cannot be ruled out as a specific consideration. A further follow-up test typically is required. A common means of measuring ankle joint com- plex flexibility is the knee-to-wall distance test. The knee-to-wall distance test is quick and easy to set up and use as a regular monitoring tool for athletes. Place a ruler or measuring stick on the floor, with 0 centimetres at the wall. With shoes off, the athlete stands with the foot flat against the floor and the heel touching the ground. The knee stays in contact with the wall, hip–knee alignment is maintained, and the knee tracks over the second toe. The athlete gradually slides the foot backwards until the heel can no longer maintain contact with the floor whilst maintaining knee contact with the wall (figure 6.12). At this point, the distance of the big toe from the wall is recorded. Pub- lished ranges suggest that 6 to 10 centimetres is normal, but there is little to support this as a functional requirement. What is probably more important than distance is symmetry between the left and right legs.

The single-leg squat (figure 6.13) is a useful follow-up exercise to the body-weight squat,

because it illustrates single-limb strength in the squatting movement. The observation points remain similar to those for the normal squat. The narrowed base of support, which is offset from the athlete’s centre of mass, increases the emphasis on maintaining a level hip position as the athlete descends.

During the downwards movements, the athlete should maintain the hip, knee and second-toe alignment and spinal alignment and not drop into anterior pelvic tilt or lumbar spine extension. The standing foot should be balanced, and no overpronation or exces- sive eversion should occur throughout the movement.

The movement should be fluid; the athlete must maintain good control throughout. As identified in chapter 4, off-centred forces cause rotations throughout a system mass. These forces need to be countered by the actions of the gluteus medius and minimus at the hip and the external obliques in the trunk to maintain a level pelvis and hip, and alignment of the knee and second toe. Similarly, the shoulders need to remain level. Rotations in the trans- verse plane at the shoulder (figure 6.14a) are symptomatic of rotations in the trunk, which

Figure 6.12 Knee-to-wall distance test.

the athlete may employ to counter rotations in the hip or lower limb and simultaneously maintain a balanced position. Valgus move- ments at the knee may also be seen if the athlete attempts to counter rotations through lower-limb rotations.

The practitioner should look at hip–knee alignment; hips and shoulders should be level and not rotated through the transverse plane.

When the athlete can no longer maintain the correct alignment or movement control, the practitioner should record the depth of the movement and note observations of compen- sations. The line of the femur provides a good marker for recording this depth. If it is at 0 degrees in standing, then ranges of 60, 90, 120 or more degrees provide sound markers for evaluation of depth.

Also of interest is the movement strategy that the athlete adopts to maintain balance in this athletic skill. With a single (and narrow) contact point with the floor, the base of support is small and slightly off-centred. To maintain balance, the athlete must move so that the centre of mass remains above the base of sup- port. Performing this action with a knee-first movement will cause the ankle to dorsiflex excessively and the knee to come in front of the toes (figure 6.14b). Ultimately, ankle flexibility

will limit the movement, not because the ankle is inflexible (as described previously) but because of the movement strategy adopted by the athlete. Similarly, an athlete who tries this ‘knee dip’ exercise by leading the movement with a rearward movement of the hips will quickly move the centre of mass posteriorly to the base of support. The trunk will then have to lean forward to redress the balance, either through greater flexion of the hip or by rounding the shoulders and flexing the tho- racic spine. These compensations also may be evident in the normal squatting movement as a strategy to maintain balance.

One of the key functions of recording such movement compensations in an athlete is to inform the coaching strategy. Often, the ana- tomical limitations within the kinesiological chain do not limit actions; instead, the athlete does not understand how these actions should be performed. In my last professional rugby league club, in a screening process for more than 35 professional players at first-grade level, only 2 had genuine anatomical restrictions to flexion at the hip and only 1 had an anatomical restriction at the shoulder. Excellent coaches understand this indicator and adopt their movement development strategies to guide the athlete into ever more appropriate movement

Figure 6.14 Common movement errors in the single-leg squat: (a) rotation of the shoulders in the trans-

verse plane; (b) poor midsection control and associated lower-limb malalignment.

sequences. Such observation notes form the basis not just for identifying movement limita- tions or compensations but also for guiding the teaching strategy. This approach is not possible if the screening tool only identifies scores such as depth of movement.

As will be emphasized in chapter 9, the ability to maintain hip, knee and foot align- ment (with the knee tracking along the line of the second toe) in landing actions is crucial in an athlete, especially when braking actions or multidirectional movements are central components of sport performance. For this reason, observing double- and single-leg land- ing movements from simple positions such as stepping off a box provides the practitioner important information about the athlete’s potential robustness (i.e., injury avoidance) in these movement contexts.

Drop jump, or step down, landings can be observed from boxes that are 20 to 40 centime- tres high. The athlete should be encouraged to step off a stable box or platform (figure 6.15a); actively jumping increases the vertical displace- ment of the centre of mass and therefore the ground reaction force on landing. The athlete should attempt a flat-foot landing that is stable

and quiet (figure 6.15b). The practitioner looks for the trunk to remain upright and stable on landing, and the hips to be square and level (i.e., one side shouldn’t dip). Alignment of the hip, knee and ankle is crucial, and the knee and hip should not sink or absorb force. The athlete should be coached to stick the landing in a solid and stable position that does not change after ground contact.

As a teaching point, to facilitate a flat-footed landing, the athlete should be encouraged to pull the toes of the leading leg up towards the knee so that there is plantargrade dorsiflexion at the ankle (i.e., the flat foot is parallel to the floor) as the athlete steps forward.

After the athlete can consistently control his or her posture in a two-footed landing, the movement can be progressed to a single-foot landing (figure 6.16). Reducing the base of sup- port makes this task much more difficult than the double-foot landing. Careful consideration should be given to the height from which the athlete steps. Depending on the competency of the athlete, reductions of 50 per cent in drop height, or a drop height of 10 to 20 centimetres in the first instance, might be considered for this action. The narrowed base of support also

Figure 6.15 Drop jump with a double-foot landing: (a) starting position; (b) stable flat-foot landing.

makes it exponentially more difficult to control the hip alignment in the transverse plane (i.e., to keep the hips level), so this activity typically highlights a weakness in the gluteus medius or minimus muscles. Medial or valgus movements of the knee are a particularly strong indicator of this weakness.

This screening activity might be especially important in female athletes during or imme- diately after peak height velocity, because the typically increased Q-angle leads to potential for increased medial forces at the knee on land- ing. This alteration in the body’s anatomical structure also predisposes the female athlete to the potential for asynchronous firing of the hamstrings and quadriceps muscles, a predis- position to knee instability in high-speed or high-force actions.

To gain a more complete analysis of a player’s movement capabilities, screening movements should incorporate highly dynamic activities that replicate an increased physio-mechani- cal demand beyond what can be induced by ground-based exercises (i.e., a foot is in contact with the floor at all times). Dynamic screens test a range of athletic qualities that influence strength, skill execution and the predisposition or vulnerability to injury. This single factor significantly increases the validity of this type of screening over slower or static screening methods.

As an exercise in lower-body muscular power, the repeated tuck jump has been pro- posed as a qualitative test that can be used to assess the neuromuscular techniques of ath- letes in jumping and landing techniques.8 _The

athlete starts in a standing position with the feet hip-width apart to enable optimal vertical force generation. The jumping movement is initiated with a rapid countermovement action (flexion of the hips, knees and ankles, and arms extended behind the athlete; figure 6.17a) that precedes a maximal vertical jump. As the ath-