Transitional Assessment: Overhead squat and Single leg Squat

 

1. Overhead Squat

The Overhead squat test (OHS) is a popular functional test used to bilateral examine and assess individual’s movement patterns, strength, flexibility, balance and neuromuscular control, as well as to identify possible risks or of musculoskeletal injury  (Clark et al., 2014; Jonhson, 2016; Noda et al., 2009). OHS requires dorsiflexion of the ankle and flexion of knees and hips (Escamilla, 2001; Lally, 2016), which allows for the comparison of bilateral asymmetries in the lower extremities.
 The OHS, along with the single squat, is used by the National Academy of Sports Medicine (NASM) to evaluate an athlete’s mobility, flexibility, and stability (Noda et al., 2008). This assessment has been shown to be highly valid and reliable measuring musculoskeletal disorders, balance, and mobility (Post et al., 2017). Indeed,  Boden et al.,(2010) reported that poor movements patterns such as knee valgus and medial knee displacement (MKD) are disfunctions usually observed during the OHS examination. Therefore, it is essential to identify and adress these dysfunctions to prevent injuries. Chalmers et al., (2017) found  an excellent inter-rater reliability (ICC=0.95) and good to excellent intra-rater reliability (ICC= 0.70-0.95).
Anterior view:

On the anterior view (figure 3) it can be observed feet externally rotate, indicating client has tightness in the soleus, lateral gastrocnemius, the short head of the bicep femoris and the tensor facia latae (TFL) (Nasm, 2006). The L-knee moves outwards (pointing outwards towards his second toe, indicating possible overactive piriformis, biceps femoris and TFL). Furthermore, the client’s arms are unlevelled, showing left arm longer than R-arm. This may be  a result of shoulder mobility, muscle weakness  of the rotator cuff, deltoid and trapezius (Maenhout et al., 2012). Client shift to his right side which may indicate a motor stability issue shift to either the right or left side during any part of the movement may indicate a motor control stability problem (Nickelston, (2011).This can be a result of tightness in the right adductor complex, TFL, Left- gastrocnemius and soleus, piriformis, bicep femoris and gluteus medius; and weakness in the right-GM, anterior tibialis and left adductor complex (Clark et al., 2014; Neurmann et al., 2010).

         Figure 1. Visual illustration of anterior view of client performing OHS.

Lateral view:

Figure 2 illustrates standing position of OHS and it can be observed excessive lordotic curve previously mentioned in the initial screening. The lumbopelvic hip complex has a rhythm, so when the APT occurs in a standing posture, there is a low back arch and hip flexion that follows suit (Nasm, 2022). Possible tight muscles causing the back arch are the hip flexor complex, psoas, iliacus, sartorius erector spinae and latissimus dorsi  (Nasm, 2022).

 Figure 2. Visual illustration lateral view of the OHS (left, initial position of OHS) (right                          deep position OHS).

Figure 3. Visual illustration showing arms falling forwards from the optimal shoulder flexion of 180°.

 

Furthermore, figure 2 shows client excessive forward lean, which may be result of thigh soleus, gastrocnemius, hip flexor complex, rectus abdominis and external obliques  or underactive  (tibialis anterior, gluteus maximus or erector spinae)(Clark et al., 2014). Additionally, Client’s arms fall forwards caused by overactive lattisimus dorsi, pectoralis major/minor, teres major, infraspinatus and coracobrachialis (Bishop et al., 2016; Nasm, 2006; Nickelston, 2011). Clark et al., (2012) and Cook et al., (2010) reported the optimal shoulder flexion should be maintained at 180°. Table 1 proposed scoring criteria, however, no normative data exits for grading system.

 

Table 1. Proposed scoring criteria for OHS suggested from NASM (Clark et al., 2015).

JOINT	COMPENSATION	LEFT	RIGHT
Foot/ Ankle	External rotation	X	X
	Fleet flatten
	Heel raise
Knee	Valgus
	Varus	X
LPHC	Forward lean	X	X
	Lumbar arching	X	X
	Lumbar rounding
Shoulder	Arms fall forward	X	X
	Elbow flexed
Head	Protruding
Score: left/Right		5	4
Total score	9

 

 

 

Posterior view:

In this plane of motion, it can be observed from the OHS assessment that the client’s right foot is more slightly pronated (eversion) compared to the left foot. Foot pronation led to tibial rotation, femoral adduction and knee valgus (Clark et al., 2014), however this is not observed in the client. Eversion may be caused by tightness of the lateral gastrocnemius, soleus and peroneal (Clark, 2010; Hirth et al., 2007). Additionally, as the lower leg moves over the foot, if the calf muscles are tight, the ankle rapidly approaches its end range of motion, and its only option is to progress forward with a collapsed mid-foot arch. It causes the foot to pronate further (Bell et al., 2011).
 

          Figure 4. Visual illustration of posterior view of client performing OHS.

2. Single Leg Squat

The single leg squat (SLS) is a useful clinical test and it is a progression of the OHS used to assess neuromuscular and movement dysfunctions in the lumbo-pelvic region such as unleveling pelvis , knee valgus or subtalar hyper-pronation (Bailey et al., 2010; Perrot et al., 2010; Perrot et al., 2010) reported the validity SLS is not the best test, as its quality can be influenced by ankle dorsiflexion range of motion (ROM) and will negatively affect the lumbo-pelvic stability diagnostic. Contrary, Ressman et al., (2019) found a inter-rater and intra-rate reliability of ICC= 0.00–0.95 and 0.13–1.00, respectively.

On figure 5, it can be observed from that when client performs SLS using left leg stance, performs the test with higher score with no apparent compensations. However, when performed on the right side appears to hike the hip on the contralateral side, outward rotate the trunk rotation and there is visible knee valgus on the stance leg (Clark et al., 2014) (See table 2 for muscle imbalances).

 

      Figure 5. Client’s illustration performing bilateral single leg squat. 

Table 2.  Movement compensation for the single leg squat assessment (Clark et al., 2016).

 

Compensation	Tight/ Overactive muscles	Weakness / Underactive muscles
Inward Trunk Rotation	Internal oblique R External oblique L TFL (R) Adductor Complex	Internal obliques (L) External oblique (R) Gluteus Medius and maximus
Hip hikes	Quadratus lumborum (L) TFL /Gluteus minimus (R)	Gluteus medius (R) (Quadratus lumborum (R)
Knee valgus	Adductor Complex Bicep femoris (Short head) Lateral gastrocnemius Vastus lateralis	Med. Hamstring Med. Gastrocnemius Gluteus medius/ Maximus Vastus medialis
Ankle	Pronation

 

References:

 

Bailey, R., Selfe, J. and Richards, J. (2011) ‘The single leg squat test in the assessment of Musculoskeletal Function: A Review.’ Physiotherapy Practice and Research, 32(2) pp. 18–23.

Bell, D.R., Vesci, B.J., and DiStefano L.J. (2011) ‘Muscle activity and flexibility in individuals with medial knee displacement during the overhead squat. Athletic TrainingSports Health Care, 4(3), pp. 117-125.

Bishop, C., Edwards, M., Turner, A. (2016) ‘Screening movement dysfunctions using the overhead squat.’ Professional Strength and Conditioning, 42, pp. 22-30.

Brookbush, B. (n.d.) Overhead squat assessment. Brookbush Institute. [Online] [Accessed on April 27, 2023]https://brookbushinstitute.com/courses/solutions-table-overhead-squat-assessment.

Chalmers, S., Fuller, J.T., Debenedictis, T.A., Townsley, S., Lynagh, M., Gleeson, C., Zacharia, A., Thomson, S., and Magarey, M. (2017) ‘Asymmetry during preseason Functional Movement Screen testing is associated with injury during a junior Australian football season.’ Journal of Science and Medicine in Sport, 20 (7), pp. 653–657.

Clark, M A, Lucett, S C, and Sutton, B G. (2012) NASM Essentials of Personal Fitness Training. Lippincott Williams & Wilkins, Fourth Edition.

Clark, M, and Lucett, S. (2010) NASM Essentials of Corrective Exercise Training. Lippincott Williams & Wilkins, Third Edition. 2010.

Clark, M.A., Lucett, S.C., Sutton, B.G. editors (2012). NASM Essentials of Personal Fitness Training. Fourth Edition. Baltimore: Lippincott Williams & Wilkins.

Escamilla, R.F' (2001) 'Knee biomechanics of the dynamic squat exercise. Med Sciences Sports Exercise,33, pp.127-141.

Hirth, C.J. and Padua D.A. (2007). ‘Clinical movement analysis to identify muscle imbalances and guide exercise.’ Athletic Therapy, 12, pp. 10–14.

Lally, E.M., (2016) 'Range of motion and plantar foot pressures in those with and without a lateral hip shift during an overhead squat.' Illinois State University.

Madhavan, S., Shields, R.K. (2010) ‘Neuromuscular responses in individuals with anterior cruciate ligament repair.’ Clinical Neurophysiology, In Press, Corrected Proof

Nasm (N.d). Overactive and underactive muscles part 2: Excessive forward lean and low back Arch. NASM. [Online] [Accessed on April 26, 2023]https://blog.nasm.org/fitness/the-nasm-cpt-podcast-ep-10.

Nasm (N.d.) Solutions table EXP - NASM. [Online] [Accessed on 11th May 2023] https://www.nasm.org/docs/default-source/PDF/overhead_squat_solutions_table-(ces-version)-(pdf-40k).pdf?sfvrsn=2. 

Neumann DA, Kinesiology of the Musculoskeletal System, Foundations for Rehabilitation 2nd ed. St. Louis, MO: Mosby Elsevier. 2010.

Nickelston, P. (2011) The overhead squat assessment. Dynamic Chiropractic. [Online] [Accessed on April 27, 2023]https://dynamicchiropractic.com/article/55111-the-overhead-squat-assessment.

Noda, T. and Verscheure, S., (2009) ‘Individual goniometric measurements correlated with observations of the deep overhead squat’. Athletic Training & Sports Health Care, 1(3), pp.114-119.

Perrott M, Pizzari T, Cook J. Single leg squat is not the best test for lumbo-pelvic stability. Journal of Science and Medicine in Sport 2010 Dec;13(Supplement 1):e58

Ressman, J., Grooten, W.J.A, and Rasmussen, Barr, E. (2019) ‘Visual assessment of movement quality in the single leg squat test: a review and metaanalysis of inter-rater and intrarater reliability.’ BMJ Open Sport and Exercise Medicine, 5, p.e 000541.