Joe Nimble

Foot structure, ankle mobility and the deep squat

“To deal with a problem effectively is to deal with the root cause” (ANON)

The deep squat is an excellent exercise to develop leg strength, joint mobility, and the skill of aligning bodyweight over the base of support relevant for running. Ankle immobility is a limiting factor to a flat-footed deep squat (Kasuyama, Sakamoto and Nakazawa, 2009), and also predicts knee injury due to compensatory knee valgus (Lima et al., 2018).Efforts to improve the deep squat by improving ankle range are often thwarted however by failure to consider foot structure.

The ‘Science of Foot Dysfunction and Cure’ posts detailed how compromised foot structure (shoe-shaped feet) creates instability and a twist of the forefoot on the rearfoot (MacConaill, 1945). The twist leads to either high-arched rigid feet, or flat-collapsed feet. Both foot types possess misaligned subtalar joints that effectively ‘block’ ankle dorsi flexion creating stiff, inflexible ankles(Manoli and Graham, 2018).

The ‘root cause’ of many deep-squat problems is,therefore, compromised foot structure that, in turn, limits ankle mobility. Limited ankle range is often just a symptom of the real problem i.e. ‘shoe-shaped feet’. If you are struggling to improve your deep squat, despite efforts to improve ankle range, compromised foot structure is the likely culprit. To improve ankle range, functional foot structure must first be restored. This is achieved by:

  1. wearing foot-shaped (functional) shoes with space for the toes to spread and the foot to widen and;
  2. loading the feet with body weight creating the force to stimulate restoration of a functional foot shape.


  • Kasuyama, T, Sakamoto M and Nakazawa R. Ankle joint dorsiflexion measurement using the deep squatting posture. Journal of Physical Therapy Science.2009; 21: 195-199.
  • Lima YL, Ferreira V, Lima P, Bezerra MA, de Olivereira RR and Almeida G. The association of ankle dorsiflexion and dynamic knee valgus: A systematic review and meta analysis. Physical Therapy in Sport. 2018;29: 61-69.
  • MacConaill MA. The postural mechanism of the human foot. Proceedings of the Royal Irish Academy, Section B: Biological, geological and chemical science. 1945; 50: 265-278.
  • Manoli A. and Graham B. Clinical and new aspects of the subtle cavus foot: a review of an additional twelve year experience. Fuss and Sprunggelenk. 2018; 16: 3-29.
Tags: mobility, foot function, activity, science, foot, function