NASM Archives - PostureScreen, LeanScreen, RemoteScreen, SquatScreen, PostureRay

SQUAT FORM – WHAT DOES IT TELL US? PART 1

BY DAVID CRUZ, DC, CSCS, FMS, SFMA

The ability to perform a squat or partial squat is an essential primal movement in life we must all be able to do, whether you are 8 or 80 years old. When we think of a squat, most of us associate the move with weight training or a specific sport activity. However, we all perform variations of a squat everyday with activities of daily living ranging from lifting a box to picking up a child or sitting down in a chair. Our ability to do this in a safe and correct manner can be the difference between injury and living a healthy, pain free life.

When done properly, the squat is a safe and effective exercise that can be used for strengthening the entire body. It is estimated that correctly performing a squat requires over 200 upper and lower body muscles to work synergistically. (17) Together, both the upper and lower body must properly work in unison to move through triple flexion and extension of the hip, knee and ankle. This exercise can also be used from rehabilitation to the sport-specific setting by simply changing the range of motion. For instance, in the rehabilitation setting, if quadriceps enhancement is the goal, then keeping the squat to less than 90 degrees is desirable since moving past this range of motion has limited benefit. (1) However, if the intent is to increase hip extensor strength, then increasing the squat depth would be beneficial. (2)

Performing a squat assessment can provide valuable information about a client and potentially reduce their risk of injury. In addition to musculature stability and postural control, dysfunctional movement patterns can also be identified. The inability to perform a squat can be a predictor of a low back or ACL injury. (2, 3, 4) In this article each body region will be discussed along with common movement faults to be aware of. Part 2 will discuss intervention strategies to correct these dysfunctions.

PERFORMING A SQUAT ASSESSMENT

Ask your client to wear shorts and a short sleeve shirt for the assessment. This will make it easier to identify faulty movement patterns. Position the client so that you can observe them from the front and side, as well as being able to observe any rotational movements in the transverse plane.

To perform a squat assessment, begin by instructing the client to stand with their feet shoulder width apart (inside of their feet aligned with the outside of their shoulders). Feet should be straight forward and arms straight above head or with hands gently behind their ears (Figure 1). This position retracts their shoulder blades and activates the upper back musculature providing stability. Their head should be in alignment with their shoulders and eyes gazing straight forward.

Figure 1

Figure 2

Instruct them to descend as far as comfortably allowed while keeping their heels on the ground and pushing the hips back as if sitting in a chair (Figure 2). The tempo should be 2-3 seconds on the way down. Do not attempt to cue them on improper movements you initially see. Have them repeat the squat 3 to 5 times. (2, 5, 6)

HEAD POSITION

Forward head posture has been associated with neck pain, shoulder pain, and temporomandibular joint dysfunction, therefore it is important to assess (Figure 3). (7, 8) Assess from the lateral (side) view watching for anterior head carriage or excessive extension of the neck. From the anterior and posterior view the head should remain in midline and not move side to side. (5, 6)

Figure 3

Eye gaze is also important to monitor as it indicates ones ability to disassociate eye from head movement. As they perform the squat, eye gaze should remain straightforward and not move upward with any head tilt. (5)

UPPER BACK AND SCAPULAR POSITION

Hyperkyphosis or excessive rounding of the upper back has been associated with forward head posture as well as limiting cervical range of motion. (9) Therefore it is important to maintain proper upper back and scapular position. When performing the squat assessment a slightly extended thoracic spine position is recommended to maintain a chest up position (Figure 4). This will also allow the scapula to be retracted. Any rounding of the shoulders and scapula protraction similar to upper cross syndrome should be quickly identifiable. (5, 6)

Figure 4

LOW BACK POSITION

Maintaining a neutral low back position with a slight lordosis is essential to proper and safe motion (Figure 5). Intravertebral disc pressure increases as lumbar lordosis is lost, putting one at risk for injury. (10, 11, 12) Therefore maintaining a lordosis throughout the squat movement is essential. It also allows for proper abdominal bracing necessary to maintain the intra abdominal pressure for proper support. (13)

Figure 5

PELVIC POSITION

Pelvic rotation and tilting should be assessed as this could be due to compensation for the low back or hip musculature. Monitor the level of the hips in relationship to the floor. If the hips lack mobility then this may be seen with excessive thoracic forward lean as the body attempts to compensate. Proper pelvic alignment also allows the muscles of the lumbar spine, erector spinae, quadratus lumborum and oblique muscles to function optimally providing support to the lumbar spine reducing the risk of injury. (5)

Figure 6

KNEE TOE ALIGNMENT

ACL injuries occur at a four to six fold greater incidence in females than males and have been associated with increased knee valgus angles. (14, 15) Therefore assessing the knee and toe alignment from the anterior and posterior view is essential (Figure 7). As the client squats down pay close attention and note if the outside of their knee crosses their medial malleolus. (5) This movement dysfunction may be the result of hip muscular weakness, an ankle dorsiflexion problem or over pronation.

Figure 7

TIBIAL TRANSLATION

There is a general consensus among fitness professionals that increased tibial translation allowing the knees to glide past the toes is harmful and should be avoided. Although knee torque increases as tibial translation occurs, there is no evidence to support ones risk of injury is increased (Figure 8). (5) Conversely, if tibial translation is limited, an increase in trunk anterior lean may occur in order to compensate. This is supported by Fry and colleagues who demonstrated limited tibial translation inappropriately transfers forces to the hips and low back. (16) Therefore as a general rule, assess whether the tibia and the spine are in parallel alignment (Figure 9).

Figure 8

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Figure 9

FOOT POSITION

A stance with feet forward, or with a slight degree of external rotation, and approximately shoulder width apart is desired as a wider stance will change the torque about the knee and hips as well as the muscle activity of the lower extremities. (2) As one descends the foot pressure should shift from the mid foot toward the heel and lateral foot during this loading phase. (5) Toes should remain on the ground to maintain balance (Figure 10). From the lateral view assess if the heel is rising, which may be due to an ankle dorsiflexion limitation of the joint or from overactive gastrocnemius muscles. (18) When assessing from the anterior and posterior view, knee valgus as noted above may be the result of an over pronation problem.

Figure 10

START POSITION KEY POINTS:

Arms extended above head
Feet shoulder width apart
Feet pointing straight
Eye gaze is fixed straight ahead

BOTTOM POSITION KEY POINTS:

Arms stay straight
No excessive forward lean
Feet stay pointing straight
Heels stay on the ground
Knees stay in line with feet

It is of utmost importance that clients are pain free when performing any movement assessment. Refer to the NASM Essentials of Corrective Exercise Training book for recommendations. Part 2 of this article will discuss appropriate corrective exercise intervention strategies based on the movement dysfunctions identified here.

REFERENCES

1) Escamilla, RF, Fleisig, GS, Zheng, N, Lander, JE, Barrentine, SW, Andrews, JR, Bergemann, BW, and Moorman, CT. Effects of technique variations on knee biomechanics during the squat and leg press. Med Sci Sports Exerc 33: 1552–1566, 2001a.

2) Schoenfeld, B. 2010. Squatting Kinematics and Kinetics and Their Application to Exercise Performance. Journal of Strength and Conditioning Research 24(12):3497-3506.

3) Chaudhari, A., et al. 2006. The mechanical consequences of dynamic frontal plane limb alignment for non-contact ACL injury. Journal of Biomechanics. Volume 39, Issue 2, 2006, Pages 330–338.

4) Myer, G., et al. 2008. Trunk and Hip Control Neuromuscular Training for the Prevention of Knee Joint Injury. Clin Sports Med 27:425-488.

5) Myer, G., et al. 2014. The back squat: A proposed assessment of functional deficits and technical factors that limit performance. Strength Cond J. 2014 December 1; 36(6): 4–27.

6) Clark, M., Lucett, S., Sutton, B. (2014) NASM Essentials of Corrective Exercise Training. Burlington, MA, USA: Jones & Bartlett Learning.

7) Ruivo, R., et al. 2014. Cervical and shoulder postural assessment of adolescents between 15 and 17 years old and association with upper quadrant pain. Braz J Phys Ther. 2014 July-Aug; 18(4):364-371.

8) Harman, K., et al. 2005. Effectiveness of an Exercise Program to Improve Forward Head Posture in Normal Adults: A Randomized, Controlled 10-Week Trial. The Journal of Manual & Manipulative Therapy Vol. 13 No. 3, 163- 176.

9) Quek, J., et al. 2012. Effects of thoracic kyphosis and forward head posture on cervical range of motion in older adults. Manual Therapy 1-7.

10) Harrison, D., et al. 1998. Elliptical Modeling of the Sagittal Lumbar Lordosis and Segmental Rotation Angles as a Method to Discriminate Between Normal and Low Back Pain Subjects. Journal of Spinal Disorders. Vol. 11(5).

11) Panjabi, M., White, A. (1990) Clinical Biomechanics of the Spine, Second Edition, USA: LWW.

12) Callaghan, J., McGill, S. 2000. Intervertebral disc herniation: studies on a porcine model exposed to highly repetitive flexion/extension motion with compressive force. Clinical Biomechanics 16:28-37.

13) Kavcic, N., et al. 2004. Determining the Stabilizing Role of Individual Torso Muscles During Rehabilitation Exercises. Spine Volume 29, Number 11:1254–1265.

14) Myer, G., et al. 2004. Rationale and Clinical Techniques for Anterior Cruciate Ligament Injury Prevention Among Female Athletes. Journal of Athletic Training. 39(4):352–364.

15) Hewett, T., et al. 2010. Understanding and Preventing ACL Injuries: Current Biomechanical and Epidemiologic Considerations – Update 2010. North American Journal of Sports Physical Therapy. Vol. 5(4):234-251.

16) Fry, A., et al. 2003. Effect of Knee Position on Hip and Knee Torques During the Barbell Squat. Journal of Strength and Conditioning Research, 2003, 17(4), 629–633.

17) Solomonow, B., et al. 1987. The synergistic action of the anterior cruciate ligament and thigh muscles in maintaining joint stability. Am J Sports Med 15: 207–213.

18) Riddle, D., et al. 2003. Risk Factors for Plantar Fasciitis: A Matched Case-Control Study. The Journal of Bone and Joint Surgery. 85-A(5):872-877.

HOW TO PREVENT ROTATOR CUFF INJURIES THROUGH CORRECTIVE EXERCISE PROGRAMMING (PART 1)

Shoulder pain and shoulder injuries are among the most common conditions within the general population and among athletes. Approximately 75 to 80% of these are caused by conditions related to the rotator cuff (1). The rotator cuff consists of four muscles, including the supraspinatus, infraspinatus, subscapularis and teres minor. These act to provide dynamic stability and control the position of the humeral head relative to the glenoid fossa during motions ranging from throwing to performing a push-up (2). There are many factors that can lead to shoulder pain and dysfunction, one being a muscular imbalance between the rotator cuff muscles and its relationship to the scapula and clavicle.

This two part series will describe the function of the rotator cuff and its synergistic relationship to the scapula and clavicle, while also providing exercises to strengthen the muscles of the shoulder complex. Correcting dysfunctional movement patterns of the shoulder complex typically requires a multifaceted approach including inhibiting, lengthening, and activating muscles whether the goal is preventative or rehabilitative. This part of the series will focus on corrective exercise strategies that inhibit and lengthen muscles by self-myofascial release in combination with static stretching. Part 2 of the series will provide you with corrective exercise protocols to stabilize and strengthen the rotator cuff muscles.

To understand how to implement corrective strategies we must first look at the anatomy and kinematics of the shoulder. The shoulder complex can be broken down into three distinct regions, the upper arm or humerus, scapula, and clavicle, which are working together providing movement in all three planes. These three regions create a mechanical linkage that is dependent upon one another for proper shoulder motion that is controlled by the upper trapezius, lower trapezius and serratus anterior.

Dysfunctional movement patterns are in part based on the concept of relative flexibility that suggests movement occurs through the pathway of least effort. For example, if hip movement is relatively stiff compared to that of the low back, then the movement is more likely to happen in the back (3). In the case of the shoulder, if the trapezius muscles are limiting proper scapula thoracic motion, the rotator cuff muscles will then compensate for this and become the “pathway of least effort” leading to compensation patterns. Therefore, inhibited or tight trapezius and serratus muscles will alter proper scapula motion. This results in improper clavicle movement due to these muscular imbalances ultimately affecting the rotator cuff.

In order to have properly working rotator cuff muscles, proper scapula thoracic motion must be established in order to maintain the correct length-tension ratio of the rotator cuff muscles. The motion of the scapula and upper arm is defined as a 2:1 movement ratio, meaning for every 2 degrees of upward humeral motion there is 1 degree of upward scapular motion. Muscles involved in creating this movement are the upper and lower trapezius and the serratus anterior. A change in scapula position or motion may cause an internal rotation of the humerus resulting in a shortened internal rotator muscle (subscapularis) and a stretched or weakened external rotator muscle (teres minor). Any dysfunction of these muscles will require opposing muscles acting on the shoulder complex to be affected due to their relationship with one another.

Proper shoulder motion and rotator cuff function are also dependent on clavicle movements that include protraction, retraction, elevation, depression and posterior rotation. As the scapula rotates upward the clavicle elevates up to 30 degrees at the acromioclavicular (AC) joint (4). Then as the arm elevates further the clavicle begins to rotate posteriorly along its axis allowing the scapula to further elevate upward.

This posterior clavicle rotation has been described in numerous studies including one by Ludewig and colleagues who performed a three dimensional analysis (5). Their findings indicate that as the arm elevates, 8 degrees of posterior rotation occurs when the arm is elevated to 110 degrees. Any loss of normal scapula motion will alter the clavicle motion and ultimately restrict the range of motion of the upper extremity. Therefore, prior to initiating any specific rotator cuff exercises it is imperative to restore the muscular function of the scapulothoracic, AC, and sternoclavicular (SC) joint regions.

In order to inhibit and lengthen these muscles a self-myofascial release (SMR) approach with either a foam roll or a tennis ball can be utilized. SMR using a foam roll has been shown to be effective for increasing flexibility when combined with static stretching. Mohr and colleagues demonstrated this when they compared foam rolling and static stretching of the hamstring muscles (6). Their study findings indicate using the foam roll for SMR in addition to static stretching is superior to either SMR or static stretching alone. Therefore, in order to maximize range of motion it is recommended to foam roll prior to static stretching.

The following protocol is based on the above-described findings and can be performed daily or at least 3 times per week. The SMR exercises are performed on the floor applying as much body weight pressure as can be comfortably tolerated for up to 1 minute at time.

Trapezius and Rhomboid SMR

Begin seated on floor. Lie back placing foam roll across upper back. Cross arms in front, placing hands on shoulders. Lift hips off floor. Slowly massage upper back, rolling up and down as tolerated, for duration of 1 to 2 minutes. Maintain consistent pressure with foam roll. If a painful area is found, stop rolling and REST on the area for 30 seconds as tolerated, then continue.

Posterior Shoulder Tennis Ball SMR

Begin lying on floor facing up. Place a tennis ball behind shoulder. Raise arm so elbow is at shoulder level and bent to 90°. Lift opposite shoulder slightly so that pressure is felt against tennis ball. Grasp wrist with opposite hand and move arm upward and downward massaging shoulder muscles. Perform massage for 1 to 2 minutes. Maintain consistent pressure with tennis ball. If a painful area is found, stop rolling and REST on the area for 30 seconds as tolerated, then continue.

Pectoralis Major and Minor SMR with Tennis Ball

Begin lying face down with a yoga or tennis ball situated between the floor and below the clavicle with forearm flat on the ground. Applying constant pressure on the ball, slowly move forearm upwards, pause momentarily, and then slowly return to starting position.

Static stretching to compliment the SMR exercises can be performed daily or at least 3 times per week. It is recommended that each stretch is held for 30-60 seconds and repeated three times resting 30 seconds in between stretches. When stretching the posterior shoulder a cross body stretch is recommended as this was found to be more effective than the side lying sleeper stretch by McClure and colleagues (7).

Cross Body Stretch

Begin seated or standing (ideally this is best done with the back against a wall to help stabilize the scapula and emphasize the stretch on the posterior shoulder). Extend one arm in front, and across body, at shoulder level. With opposite arm grasp arm above elbow and gently pull towards chest until a stretch is felt in the back of the shoulder. Hold for 20-30 seconds and repeat on opposite side.

Static Foam Roll Chest Stretch

Begin by positioning yourself lying on foam roll with feet flat on floor. Foam roll should support the head and run along the spine down to pelvis. Place arms to sides. Bend both elbows to 90º at shoulder level with palm facing up. Relax as chest and shoulders stretch for 30-60 seconds. Do not try to force arms to floor.

All of the above displayed exercises are easy to execute and include minimal risks if performed as described. To achieve satisfying results it is important do them on a regular basis and for a minimum of 4 weeks.

References

(1) Clark, M.A., Lucett, S.C. (2014). NASM Essentials of Corrective Exercise Training. Burlington, MA. Jones & Bartlett Learning.

(2) Arnheim, D.D., Prentice, W.E. (2000). Principles of Athletic Training. Boston, MA. McGraw Hill.

(3) Lehtola et al. BMC Musculoskeletal Disorders 2012.

(4) Kisner, C., Colby, L.A. (2002). Therapeutic Exercise Foundations and Techniques. Philadelphia, PA. F.A. David Company.

(5) Ludewig, P., et al. (2004). Three-Dimensional Clavicular Motion Durning Arm Elevation: Reliability and Descriptive Data. Journal of Orthopaedic & Sports Physical Therapy, 34(3), 141-150.

(6) Mohr, A., et al. (2014) Effect of foam rolling and static stretching on passive hip-flexion range of motion. Journal of Sport Rehabilitation.

(7) McClure P, et al. (2007). A randomized controlled comparison of stretching procedures for  posterior shoulder tightness. Journal of Orthopaedic & Sports Physical Therapy 37:108-14.

DAVID CRUZ, DC, CSCS, FMS, SFMA

Dr. David Cruz practiced as a sports chiropractor for 18 years treating athletic injuries, from weekend warriors to professional athletes. He received his bachelor’s of science degree in athletic training and has completed graduate course work in kinesiology. He is a Certified Strength and Conditioning Specialist (CSCS) as well as having both FMS and SFMA certifications. The combination of his background in sports medicine and interest in technology made him passionate about bringing these two worlds closer together, resulting in the foundation of his company WebExercises in 2005.
WebExercises is an end-to-end solution for exercise rehabilitation professionals and is currently integrated with several EHR companies. In addition to WebExercises, Dr. Cruz is co-founder and partner of two other software businesses within the health care and technology industry.