Biokinetic Analysis of the Foot & Ankle

This literature review argues that clinically we need to observe functional - rather than conventional - biomechanics at the ankle and foot. Functional biomechanics observes that all segments in a joint can be simultaneously mobile. The authors suggest that:

"The reader should be able to understand how the 3-dimensional biokinetic analysis of the ankle and foot can contribute along with imaging examinations to the clinical setting, thus allowing the construction of a more complete profile of the patient."

Metsavaht L, Leporace G. Current trends for the biokinetic analysis of the foot and ankle. J Foot Ankle. 2020;14(2):191-6.

Key Points: Biokinetic Analysis Of The Foot & Ankle

• The central nervous system works as the generator of complex movement patterns based on muscular synergies; the control of active joint stability is coordinated by the neuromuscular system and not by isolated muscle strength or range of motion.

• Functional ankle stability is mostly related to the capacity of triceps surae muscle to generate functional strength.

• The main structure that generates stability in gait is the foot; functioning as a stable base of support for movements of the proximal segments, the foot assists in the absorption of ground reaction forces and is a powerful lever arm for the ankle muscles during the propulsion phase of gait.

• The medial longitudinal arch (MLA) is essential for the proper functioning of the foot, working as a spring system, changing foot stiffness and allowing deformation for absorbing loads while transferring forces to the ground.

• The MLA works as a three-dimensional rather than two-dimensional structure.

• Resection of the plantar fascia can reduce foot stiffness by 25%; removal of the transverse arch can reduce foot stiffness by more than 50%.

• The functionality of the plantar fascia can be observed via the windlass mechanism, whereby hallux extension produces a tension in the plantar aponeurosis, creating a lever arm for propulsion.

• The role of eccentric control synergies is increased in running vs walking.

Gait Cycle; Biocinetica Laboratório do Movimento Ltda, Rio de Janeiro, Brazil.

Running Cycle; Biocinetica Laboratório do Movimento Ltda, Rio de Janeiro, Brazil.

• Chronic ankle instability can lead to changed movement patterns at the hips and knees.

• Issues at the proximal end of the chain can also influence the foot and ankle distally.

• Inhibition of peroneus longus is associated with continued ankle instability, even when triceps surae strength has returned.

• Ankle stability is task-dependent, and therefore direction-dependent.

• The functioning of foot and ankle is dependent on activity of passive tissue and muscles and neuromuscular control of local and distant joints.

Clinical Pilates in practice

• There's reason that we often start with footwork - but make it dynamic!

• For "toes on" footwork, ensure that the MTPJs are on the bar, encouraging a press into the forefoot to find hallux extension and wind up the plantar fascia to raise the heels.

• Encourage eccentric support and control of the feet and ankles through load.

  → Jump Board on the Reformer.

  → Calf Raises.

• Build foot posture and positioning into all hip/knee and lower limb work.

  → Feet in Straps and Leg Springs.

• Be sure to work on peroneal support around the ankle.

  → Foot Waving.

  → The Foot Corrector and the Toe Gizmo can be integrated into standing work.

• Ensure hip and knee alignment and strength are addressed, rather than focusing solely on ankle stability.

• Change it up: wide stance, split stance, hip internal rotation, knee flexion, dorsiflexion.

  → Change foot and ankle position to reflect the functional task.

References

1. Cavalin, GA; Zeitoune, GG; Leporace, G; Nadal, J. Coordenação intersegmentar do quadril e do tornozelo em corredores recreacionais. In: 26o Congresso Brasileiro de Engenharia Biomédica, 2018, Búzios. Anais. Rio de Janeiro: SBEB; 2018

2. Venkadesan M, Yawar A, Eng CM, Dias MA, Singh DK, Tommasini SM, et al. Stiffness of the human foot and evolution of the transverse arch. Nature. 2020. 579(7797): 97-100