Impairments in lower extremity movements are usually characterized by excessive foot pronation (i.e. flat foot), increased knee valgus (i.e. tibia internally rotated, femur internally rotated and adducted or “knock-kneed”), and increased movement at the lumbo-pelvic-hip complex (LPHC) during functional movements (Clark, Luccett, & Sutton, 2014). When performing a squat, the generation of external rotation allows for stability (Starett & Cordoza, 2016). Where, stability is the measure of the ability to return to a desired position following a disturbance to the system (Miller, 2012).
Try placing your middle finger over your index finger in the right hand and then grabbing the two fingers with your left hand (as shown in Figure 1):
Next, try rotating the fingers externally (to the right) with the left hand and then rotating the fingers internally (to the left) while keeping a tight grip.
What do you notice?
When externally rotating the fingers, you should feel as if the fingers in your right hand are tighter compared to internally rotating the fingers to the left. The same happens when you externally and internally rotate the knee joint. Thus, externally rotating the knee may prevent from the knees collapsing in. A good coaching cue that I use to prevent knee collapse or knock-knee when performing the squat is to: “corkscrew your feet into the ground.”
Clark, M., Lucett, S., Sutton, B. G.(2014). NASM essentials of corrective exercise training. Philadelphia, PA: Wolters Kluwer.
Miller, T. (2012) NSCA’s guide to tests and assessments. Champaign, IL: Human Kinetics.
Starrett, K., & Cordoza, G. (2016). Becoming a supple leopard: The ultimate guide to resolving pain, preventing injury, and optimizing athletic performance.Victory Belt.