The Back Squat: Targeted Training Techniques to Correct... : Strength & Conditioning Journal (original) (raw)
INTRODUCTION
The back squat is a well-researched and widely used exercise that can enhance an individual's ability to develop a fundamental movement competency for optimal mechanical strategies during a broad range of activities (2,10,13,21,25). Technical proficiency during squatting is beneficial for youth to help them correct and master optimal movement strategies during growth and development (12,13). Likewise, the squat exercise can help youth and young adults to improve physical performance and health (18,21). Adult and elderly populations can use the squat exercise to promote daily living independence during activities, such as sitting and lifting (26). Based on the lifelong benefit of the back squat, the ideal opportunity to master the movement is likely during youth when the neuromuscular system is highly plastic (23).
Training interventions that incorporate squatting exercises have been shown to improve physical performance and to decrease modifiable risk factors associated with sports-related injuries (8,9,16,17,21). Correct and consistent squat performance is a prerequisite to safe progression to more intense training activities involving more dynamic or high-load squat-related exercises (18). The back squat can function as both a fundamental training exercise and a screening tool to identify and correct functional deficits (22). Specifically, we have previously outlined ideal back squat technique with 10 position and movement criteria and pinpointed 30 functional deficits that can be identified with the back squat assessment (BSA) (22). The purpose of this follow-up commentary is to provide corrective strategies for each biomechanical deficit criteria (22). The following proposed exercises to supplement the BSA, inclusive of corrective cues, are designed to be effective training tools to enhance the delivery of back squat exercise instruction by practitioners. It is hopeful that these proposed tools will result in improved physical health and ability for individuals of all training levels through deficit correction and optimal technique acquisition of the back squat.
CORRECTING FUNCTIONAL DEFICITS
The underlying deficits for incorrect back squat performance may be due to a myriad of limitations, including miscomprehension of exercise instruction, poor neuromuscular coordination and recruitment, insufficient muscular strength or joint stability, and/or joint immobility (22). The use of systematic analyses may help guide practitioners as they identify the underlying biomechanical or neuromuscular deficits responsible for poor back squat performance (22). Once deficits have been identified, or are reasonably suspected, targeted corrective interventions can be implemented to begin to ameliorate functional deficiencies.
Practitioners should initiate corrective interventions by first assessing for miscomprehension of task instructions as the potential underlying cause for insufficient back squat performance. Instruction for the back squat must be clear, concise, and age appropriate (22,23). If an athlete continues to demonstrate incorrect back squat technique, the practitioner should attempt to re-emphasize the instructions and/or provide a visual demonstration of the desired movement (e.g., instructor demonstration, peer observation, video analysis). If performance remains hindered, the practitioner is encouraged to then use corrective cueing in an attempt to improve technique.
Cueing can assist in correction for miscomprehension of instructions and poor neuromuscular coordination and recruitment. Cues can be in the form of verbal instruction, physical manipulation, and/or visual aids; all of which have potential to aid an athlete in achieving the desired technique and mechanics during the back squat. Verbal cueing, such as simple word instruction, can assist a person to modify their technique by helping them to cognitively focus on a specific positional deficit or movement phases. An example of a simple verbal cue for each of the 10 back squat criteria is presented in Table 1 (22). Physical cueing, such as light tactile guidance from a coach or training aid (e.g., resistance bands), can support the desired correct positioning that can benefit a myriad of related deficits. For example, a practitioner can lightly press on the lateral portion of the individual's knees during the descent phase of a squat if they tend to demonstrate active valgus, or inward knee movement, as a means of providing a proprioceptive cue to correct positioning. In addition, visual cues, such as video footage of correct form or the use of a mirror, can support an individual to self-correct their form as initial corrective strategies. Practitioners can significantly help their athletes identify and prioritize back squat deficits with targeted cueing strategies that are specific to an athlete's most egregious deficits. Specific and prioritized cueing can help optimize an individual's performance response and adaptions to the back squat.
Verbal cues for the back squat
Instructions or feedback provided by practitioners is often directed to body movements (e.g., “keep your knees over your toes”) (1). Regarding motor learning, this type of attentional focus is termed internal focus. However, an external focus of attention is induced when an athlete's attention is directed toward an outcome (1). External focus instructional strategies may enhance cueing and skill acquisition more efficiently than internal focus strategies and increase the transfer of improved motor skills to sports and daily living activities (1). Research of motor learning has demonstrated beneficial effects of instructions that induce an external focus (1). For example, newly learned motor skills with an external focus may be more likely to become automatic and retained. An example of using an external focus during the squat is to have an athlete visualize sitting back for a chair (1). Although the current discussion breaks down squat technique into several position and movement criteria, which may promote internal focus on discrete body movements, it is recommended for practitioners to use external focus feedback strategies when possible to improve motor learning and retention of correct squat technique (1).
If an individual's performance improves immediately through direct means of improved instruction or simple cueing (verbal, physical, and visual), it is probable that their primary limitation from performing the back squat with correct form was due to their unfamiliarity with the movement pattern that they were being asked to perform. If the individual is still unable to achieve desired exercise technique through feedback attempts, neuromuscular deficiency, strength and stability, or mobility limitations may be at the root of their failure(s). Consistent inability to demonstrate desired technique can be addressed next with targeted corrective exercise to ameliorate the specific deficits (22).
TARGETED EXERCISE PROGRESSIONS
The corrective exercise progressions presented in this commentary are organized into the 3 major deficit categories: neuromuscular, strength and stability, and mobility limitations. The BSA differentiates the analysis of the back squat into 10 specific criteria to guide practitioner's assessment of the athlete. In the current commentary, we propose 3 associated progressive exercises to target each specific deficit category (neuromuscular, strength and stability, and mobility) for each criterion (22). Each proposed exercise is supplemented with a description of the desired exercise. In addition to each description, a rationale, cue, and a picture example of an athlete demonstrating the exercise are provided.
The progression scheme is designed to begin with the first corrective exercise for a category and continue to correct a particular biomechanical deficit. However, some athletes may respond to different exercises over others due to variations in anthropometrics, skill sets, and training age. Therefore, the progression tool is only a supportive tool second to a practitioner's best judgment that should be based on the principles of pediatric exercise science and practical experience. It is outside of the scope of this commentary to include proposed volume and intensity (e.g., sets, resistance) for these exercises as these factors should be individualized and relative an athlete's entire training regimen. Nonetheless, it is highly recommended that an athlete demonstrates consistent and sound technique at lower intensity activities and volume before increasing these exercise prescription variables. In addition, practitioners should be cognizant and thoughtful of each individual's biological, training, and cognitive ages when integrating the back squat into the training program (23).
The selected exercises use a mixture of cueing, compensatory assistance, and resistance. When instructing the back squat, it is important to differentiate between cueing and compensatory assistance. Compensatory assistance from the instructor provides external physical assistance to improve exercise performance, whereas cueing is strictly cognitive feedback that requires the individual to use their inherent strength and mobility qualities without additional external assistance. Compensatory assistance makes an exercise easier to perform to guide an athlete's awareness of correct form and how correct form should feel. For example, a practitioner can provide an athlete with assistance such as using a horizontally held dowel rod for the athlete to hold during a back squat. With assistance, the athlete can more easily reach back into a squat to learn what it feels like to properly recruit posterior chain musculature by “reaching back.” Resistance provides a stimulus that counteracts an individual's inherent strength and mobility for the primary purpose of strength and stability training. Moreover, resistance training not only promotes the strengthening of muscles but also may provide a physical stimulus to make an individual more cognitively aware of their technique to promote correction. For example, during a front squat, an athlete is made consciously aware of a load pulling their trunk into flexion, and they must focus on recruiting their back musculature to counter this tendency. As a result, they are improving their neuromuscular ability to maintain their trunk at the desired angle due to this physical stimulus. Typically, if an athlete's technique improves when resistance is applied as a stimulus, neuromuscular deficiency or lack of understanding of a desired task may be the most probable limitation for inadequate performance.
Several strategies are suggested in this article to help guide the correction of back squat performance. It is warranted that deficits are corrected 1 at a time, and the most egregious deficit should be the targeted focus. By focusing on 1 deficit at a time, modifying mechanics will be more manageable and goal driven. In addition, more egregious deficits may be driving other observed deficits that may naturally improve after the first deficit is corrected. Some trial and error should be expected; however, a practitioner must first and foremost ensure safety of their participants. If an athlete indicates pain or discomfort during any of the following exercises, it is advised to immediately cease training and consult a qualified health care provider.
BACK SQUAT CRITERIA
Similar to The Back Squat: A Proposed Assessment of Functional Deficits and Technical Factors That Limit Performance (22), corrective intervention of the back squat will be discussed in 3 comprehensive domains that highlight 10 technique criteria (22). These criteria are comprised of neuromuscular, strength and stability, and mobility improvement strategies to guide systematic corrective intervention.
DOMAIN 1: UPPER BODY
- Head Position.
- Thoracic Position.
- Trunk Position.
DOMAIN 2: LOWER BODY
- Hip Position.
- Frontal Knee Position.
- Tibial Progression Angle.
- Foot Position.
DOMAIN 3: MOVEMENT MECHANICS
- Descent.
- Depth.
- Ascent.
DOMAIN 1: UPPER BODY
Domain 1 focuses on the musculoskeletal components of the head, neck, and torso that are responsible for maintaining postural control during the back squat.
Head position
Corrective strategy
Most athletes will possess adequate neck stability and mobility to execute the back squat. Neck stability is essential to provide support to the cervical vertebrae (4). Verbal and tactile cues will generally be sufficient to assist an athlete to recognize and maintain a neutral head position throughout the squat. Adequate strength, stability, and physiological range of motion are imperative for more intense variations of the back squat that integrate external resistance. When instructing head position during the back squat, ensure that the athlete can self-identify and maintain a neutral head position throughout the squat before increasing intensity. It is not recommended to perform corrective training exercises if there is any discomfort to the head or neck. Mobility limitations or pain may indicate a more substantial underlying medical problem. It is warranted to seek advice from a qualified medical professional if the athlete has prolonged neck or head limitations during the unloaded back squat. Table 2 shows exercises that are recommended to improve head position awareness, neck strength and stability, and neck physiological range of motion for the squat.
Head position
Head position
Head position
Head position
Thoracic position
Corrective strategy
Corrective schemes for the thoracic position should focus on ensuring an athlete has the abilities to tightly retract the shoulder blades and hold the chest up and open throughout the squat to promote ideal thoracic spine support. Practitioners may benefit from using neuromuscular focused corrective exercises initially to address lack of scapular retraction, forward rolled shoulders, and/or a chest that is not held upward. The athlete should be given cues, which can help them disassociate their upper torso from their lower torso as chest position is independent from trunk angle. Verbal cues such as “keep your chest up,” “pinch shoulder blades together,” and “bend the bar around you” will encourage a proper setup with thoracic position before movement initiation. If necessary, a practitioner can provide tactile cueing to the athlete's shoulders to correct position and to encourage the athlete to maintain correct posture throughout the exercise. A training technique is to place a finger between the athlete's shoulders and instruct them to pinch the finger with their scapulae throughout the squat. In addition, the wooden dowel used in this assessment serves to assist the athlete in assuming a correct chest and shoulder position. If the athlete continues to demonstrate poor thoracic position during the back squat, then the deficit may be due to strength limitations of the upper back and/or lack of mobility. In particular, excessive tightness of the chest may hinder an individual's ability to widen their chest and retract their scapulae. For example, upper crossed syndrome, where an individual has tight pectorals and upper trapeziuses with weak deep neck flexors, rhomboids, and lower trapezius, affects posture as seen with increased cervical lordosis and thoracic kyphosis, elevated and protracted shoulders, and rotation or abduction and winging of the scapulae (14). Mobility exercises of the chest along with strengthening exercises of the upper back may help athletes improve their ability to tightly retract their scapulae. Table 3 shows corrective exercises proposed to improve deficits in thoracic positioning during the back squat.
Thoracic position
Thoracic position
Thoracic position
Thoracic position
Trunk position
Corrective strategy
Trunk position corrections are primarily focused to address excessive trunk flexion and/or rounding (kyphosis) of the lumbar spine. If the athlete demonstrates excessive trunk flexion, verbal commands, such as “point your belly button straight ahead” or “straighten your torso,” may be helpful for the athlete to improve their posture. Furthermore, instructing the athlete to hold their arms overhead or use a light load to hold may provide a physical stimulus to position their trunk more erect.
If posterior pelvic tilt or kyphosis (rounding of the back) is present during the maneuver, corrective strategies should first aim to ensure the athlete learns to obtain and maintain a natural, lordosis of the lumbar spine. This can first be demonstrated during normal standing activities. Once it is clear that the athlete understands the desired position, more dynamic spinal extension and antiflexion exercises may be warranted to help them correct spinal flexion deficits with neuromuscular focused exercises and corrective cueing.
Lack of mobility of the hip flexors (iliopsoas) and trunk flexors (abdominals) can also inhibit the athlete's ability to obtain correct trunk posture. The squat movement requires sufficient spinal mobility to assume and maintain slight lordotic posture. Otherwise, individuals may tend to take forward posture and place excessive intradiscal pressure to the low back, especially if the head is forward as well. If the athlete flexes at the spine before approximately 120° of hip flexion when squatting, they may have restriction in the posterior fibers of the Iliotibial (IT) band that insert into the gluteus maximus or lack of lumbar control. If an athlete demonstrates excessive trunk flexion and/or a kyphotic lumbar spine during the back squat, the exercise progressions demonstrated in Table 4 are recommended.
Trunk position
Trunk position
Trunk position
Trunk position
DOMAIN 2: LOWER BODY (TRIPLE EXTENSION)
Domain 2 encompasses the musculoskeletal components of the 3 major joints (ankle, knee, and hip) of the lower body associated with the movement phases of the squat exercise.
Hip position
Corrective strategy
The hip position criterion focuses on the frontal plane position of the hips. Constructive feedback is encouraged to help the athlete concentrate on keeping their hips level and to resist the tendency to overcompensate with their dominate side as observed with mediolateral hip dropping. Cues, such as “stay square” and “keep your hips even,” can be verbalized to promote pelvic stabilization. A visualization strategy to use is to instruct an athlete to envision an invisible column that surrounds them or envision them as a piston of a motor, which can help them stay within the confines of the column by not allowing their hips to move mediolaterally. If hip position remains uneven, asymmetric strength of the hips or hip immobility may be the culprit for an observed deficit. The exercise progressions in Table 5 are recommended to promote level hips throughout the squat.
Hip position
Hip position
Hip position
Hip position
Frontal knee position
Corrective strategy
Knee valgus or varus can be improved with neuromuscular training that incorporates various forms of immediate feedback. Progressions of triple extension resistance exercises and progressive plyometric training have been shown to decrease valgus knee moments (21). Cues that instruct the athlete to keep their knees apart during both descent and ascent are recommended. Elastic bands placed around the knees can provide a tactile cue that promote athletes to press their knees outward to assume proper knee mechanics during the squat. In addition, using a mirror or providing video evidence of frontal plane movement deficits (e.g., dynamic valgus) to an athlete can assist them in becoming self-aware of an often unknown movement deficiency.
Emphasis on improving the strength and function of the athlete's gluteal complex may have the greatest effect on limiting valgus knee angle during squatting (3,7,8). Weakness of the gluteus medius and maximus may result in coupled femoral internal rotation and adduction during the squat, which contributes to observed dynamic knee valgus. Since the gluteal muscles have a large role in both femoral external rotation and abduction, exercise selections that improve the strength and control from these powerful muscle groups will likely translate to the reduction of knee valgus during squatting (24). Suggested exercises include variants of the squat exercise that have a focus on recruitment and activation of the posterior chain.
Valgus can also be influenced by quadriceps dominant muscle recruitment relative to the hamstrings (6). Extensive research of anterior cruciate ligament injuries in the female athlete population has shown that low hamstring to quadriceps ratio is directly associated with dynamic valgus knee movement (6,9,11,20,27). Exercises that strengthen the hamstrings are warranted for those individuals who demonstrate active knee valgus. Phrases, such as “knees out,” “spread the floor,” “tear out of the outsides of your shoes,” will help give the athlete some internal cueing, which may lead to improved biomechanics. The exercise progressions in Table 6 are recommended to optimize knee frontal plane control during the back squat.
Frontal knee position
Frontal knee position
Frontal knee position
Frontal knee position
Tibial progression angle
Corrective strategy
Tibial progression angle deficits may be best targeted with movement exercise cues focused at the hip joint and potentially with mobility improving exercises for the lower leg. Practitioners may be best advised to avoid specific cues that restrict forward knee movement as this can migrate more load onto the lumbar spine (25). Typically, tibial progression angle, influenced by passive dorsiflexion at the ankle joint, will be influenced by flexibility of the calf musculature and mobility of the ankle joint. Alternatively, the athlete could maintain their heels on the ground and have excessive tibial progression angle due to a quadriceps dominant squat. Providing cues, such as “sit back into the squat” and “drive through the hips” are appropriate here. Video cueing of the athlete may be appropriate to influence self-evaluation of their tibial progression angle as it may be difficult to self-assess from the lateral perspective in real time. It is imperative that the heel maintain contact with the ground as tibial progression angle is monitored. If the athlete continues to demonstrate excessive forward tibial translation, the exercises in Table 7 are recommended to help ameliorate this technical deficit.
Tibial progression angle
Tibial progression angle
Tibial progression angle
Tibial progression angle
Foot position
Corrective strategy
The athlete should be encouraged to keep their entire foot on the ground throughout the squat with pressure toward the lateral aspect of the foot and the heel. Verbal cues, such as “keep heels down,” “press down with heels,” and “sit through the heels,” can help optimize foot and ankle position, especially if the deficit is primarily neuromuscular in nature. If the sides of the foot come off of the ground due to excessive ankle inversion or eversion and cueing does not improve form, the limitation may be associated with ankle strength imbalances. The medial aspect of the foot rising off of the ground may not be as egregious of a deficit as the lateral aspect of the foot coming off of the ground. Placing excessive pressure on the inside of the foot may underlie undesirable knee positions, such as valgus. Inability to keep the heels down may be due to tightness in the posterior chain (e.g., gastrocnemius and soleus tightness). Posterior chain stretching and dynamic mobility drills can improve the ability to keep the heels down if the deficit is due to muscle tightness or immobility. It is important to remember that foot pronation can be a normal weight-bearing function of the foot when equal parts are shared by the multiple joints of the foot (rearfoot through forefoot); however, excessive pronation may limit the potential for a more rigid and stable base of support. Without an ideal base of support by which force can be adequately directed, squat performance may be diminished. If the athlete raises any part of their foot off the ground or demonstrates excessive foot pronation as well as ankle inversion or eversion, the exercise progressions in Table 7 are recommended.
DOMAIN 3: MOVEMENT MECHANICS
Domain 3 analyzes the kinematics of the squat and discusses the limitations from functional deficits on proper movement mechanics.
Descent
Corrective strategy
The descent should be initiated with the breaking of the hips (“hip hinging”) while maintaining a rigid upright trunk (22). The corrective techniques for proper descent during the squat can include both a physical and proprioceptive stimulus to achieve desired descent performance (Table 8). The key areas to focus targeted correction for descent deficits are to ensure adequate strength and mobility for a prescribed hip-hinge descent strategy, upright torso, and correct eccentric speed control. Practitioners should encourage athletes to initiate the back squat movement with a “break” at the hips and to immediately sit back on the heels. The athlete should be instructed to flex the hips, knees, and ankles to lower the body to the correct depth where the top of the thighs are at least parallel to ground without disjointed deviations noted at the knee, ankle, or hips. One of the most common deficits presented with descent of the back squat is the use of a knee focused strategy (pressing knees forward) rather than a hip focused strategy that reaches back with the gluteals during descent. Verbal cues of “reach back” with the hips or having the athlete perform the wall tap exercise (as described in Table 9) may help influence desired descent strategy. We propose that back squat descent should be prescribed to take at least twice as long as the ascent and descent should maintain a consistent rate throughout the entire range of motion. The athlete should avoid descending too rapidly or “collapsing” due to the loss of eccentric control near the apex of depth (15). Strengthening exercises that focus on the eccentric control of the posterior chain can help correct this particular deficit. Additional strength or mobility deficits in the trunk, hip, and lower extremity musculature may impair proper descent. Targeted interventions are listed in Table 9 to improve the athlete's ability to use the appropriate hip-hinge strategy, maintain a controlled movement speed, and maintain an upright torso throughout the back squat.
Foot position
Foot position
Foot position
Foot position
Depth
Corrective strategy
At the proper depth, the femurs should be slightly below parallel to the ground, hips are back, tibias are positioned vertical, and feet are entirely on the ground. The most common deficit of depth during the back squat is from the athlete squatting to a position that is too shallow. Targeted feedback and cueing may be most advantageous to correct squat depth deficits. For example, physical cues, such as a box at the appropriate depth, can be used as a target. Athletes should use prescribed descent strategies that achieve thighs at least parallel to the ground. If the athlete cannot demonstrate desired technique throughout descent, it is recommended to use assistive strategies, such as a practitioner-held dowel (Table 10). While squatting below parallel can occur, it is not often detrimental to the athlete. If contraindicated based on existing pathology, excessive squat depth can be easily corrected with targeted cueing and feedback or box squat techniques.
Inability to achieve depth may also be due to a lack of lack isometric strength of the posterior chain to maintain bodyweight support at the apex of depth. Strengthening the posterior chain using isometric strengthening drills may help an athlete assume and maintain a deep hold position at the apex of the squat in good form. Furthermore, tightness in the posterior chain musculature and hip adductors may further limit the ability for an athlete to achieve appropriate depth. Mobility drills that support improvements in mobility of the hip adductors and posterior chain can facilitate an athlete's potential to achieve proper back squat depth. In some cases, inadequate hamstring strength may be the culprit of a back squat that does not achieve proper depth, and thus, hamstring mobility and stretching drills are warranted in some training scenarios. The exercises in Table 10 are intended to improve squat depth ability and form.
Ascent
Corrective strategy
Assessing the underlying mechanisms associated with improper ascent technique is critical for targeted deficit correction. It is most important to ensure that the athlete drives with their hips as the primary mover and ascends while keeping their torso upright. The vertical distance between the hips and shoulders should be kept constant throughout the squat. Cueing that encourages athletes to “lead with their chest” or “rise with the shoulders” may be effective to ensure the athlete does not rise with their hips too quickly. If the athlete does rise with their hips too quickly, the vertical distance between the hips and the shoulder will decrease and will be a suboptimal movement strategy. Neuromuscular training that promotes hip drive (i.e., hip extension) is recommended as well as drills that encourage an upright torso position during ascent. Hip drive can be improved through various hip extension exercises that improve explosive concentric muscle actions of the posterior chain. Finally, it is important to ensure adequate mobility of the thoracic spine and hip flexor mobility to encourage execution of the prescribed ascent technique (22). The exercises in Table 11 are intended to target correction of the ascent movement strategy.
CONCLUSIONS
The corrective strategies for the back squat exercise are aimed to teach and generate competency in an essential functional movement for physical and daily living activities. The proposed corrective interventions are not intended to train athletes with the goal for maximum competitive load during the squat and the authors acknowledge that technical variants exist, which may increase the potential to achieve maximum back squat load. However, the current systematic approach is aimed to teach bodyweight squat technique that can serve as a precursor for more intense physical activity and training exercises (5,18,19). Furthermore, optimal movement strategy retention gained from the proposed targeted training plan may decrease the risk of injury during anticipated and unanticipated physical activity (23). The described methods for targeted exercise correction are designed to provide a systematic guide focused to improve biomechanical squat performance and rectify deficits that underlie undesirable movement patterns. Through the implementation of a corrective intervention plan for biomechanical back squat deficits, athletes young and old will be poised to achieve substantive gains in physical performance, decrease the risk of sports-related injury, and hopefully, increase their quality of life by promoting a movement pattern that will support lifelong participation in physical activity.
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Keywords:
back squat; squat; corrective exercise; training intervention; fundamental movement
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