16 I Winter 2019 www.anjc.info Legislative Update LegalEase LEGAL Q&A CHIRO ASSIST TECHNIQUE Council REHABILITATION Council OUR HEALTH By Dr. Donald C. DeFabio Chair, ANJC Physical Rehabilitation and Performance Council The previous article in this series discussed the use of the unloaded back squat assessment (BSA) as a tool for biomechanical faults as well as a func- tional exercise for ADLs, sport and injury prevention. Kushner, et al proposed normative values for standardization of the BSA which included a shoulder width stance, neutral spinal curves that are maintained throughout the movement, tops of the thighs to at least parallel to the ground as the appropriate depth and maintenance of the tibia/torso line at all times, figures 1-3. Kushner prefers to enhance spinal stiffness by taking (and holding) a deep breath and “bending the bar” (to engage the scapular depressors and retractors) before beginning the assessment. To begin, the instructions are: “Squat down until you believe your thighs are parallel to the ground and then return to the starting position.” Kushner recommends 10 repetitions, and any deficit that is demonstrated in two or more repetitions is considered a positive finding. The patient is observed for movement quality. Any inability to maintain smooth, symmetrical and coordinated movement patterns in either the descent, depth or ascent phases of the BSA is a positive finding. Furthermore, integrity of movement and alignment need to be assessed in the frontal and sagittal planes. This article will discuss the descent, depth and ascent phases of the BSA in detail as we continue our discussion. The Descent: •  A proper descent involves both physical and proprioceptive stimulus •  The rate is consistent •  Begins with breaking of the hips (hip hinge) and sitting back on the heels – a hip focused strategy •  Maintain tibia/torso line throughout – Figure 1 •  Avoid driving the knees forward – a knee-focused strategy •  Emphasize the eccentric nature of the descent: 2 - 4X longer than the ascent Note: Eccentric control of the descent requires isometric strength of the hamstrings, gluteal complex and lumbar extensors •  Avoid descending too rapidly or collapsing at the bottom – ballistic knee flexion to the point where the calves touch the hamstrings increases tension on the ACL •  Loss of joint motion in the hips, knees, ankles or feet will create asymmetrical descent findings: be sure your patients get adjusted to treat and prevent these imbalances Depth: •  Femurs to at least or slightly below parallel to the ground with the feet entirely on the ground •  Calves should not touch hamstrings •  Shallow depth may indicate lack of isometric strength in the posterior chain – hamstrings, gluteal group •  Tightness in the posterior chain, especially the hip adductors, may also prevent proper depth Note: Training from 20 – 90 degrees of knee flexion has been shown to maximally activate the gluteus medius. Shallow depths promote quadriceps dominance and controlled knee flexion below parallel has not been shown to add excessive load on the knee. Furthermore, the ability to perform a bodyweight squat at or below 90 degrees of knee flexion with proper symmetry and coordination is a good indicator of overall movement quality. Inability to squat at or below 90 degrees with symmetry and control may imply generalized stiffness or restricted joint mobility and/or stability. Relevant Rehab: The Back Squat: How Low Should You Go? Fig. 1 Fig. 2 Fig. 3