Three-dimensional variations in the lower limb caused by the windlass mechanism

Area of Science:

• Biomechanics
• Podiatry
• Kinesiology

Background:

• The windlass mechanism is a biomechanical effect of first metatarsophalangeal joint (1st MTPJ) extension.
• Understanding this mechanism is crucial for analyzing lower limb kinematics.

Purpose of the Study:

• To quantify leg movement generated by 1st MTPJ extension using the Bioval® sensor system.
• To investigate the relationship between 1st MTPJ extension angles (45° and maximal) and lower limb joint kinematics.

Main Methods:

• A pre-post-test study design was employed with a single intervention group.
• Participants (age ≥ 20) with specific foot postural parameters were included.
• Exclusion criteria included prior foot/leg surgeries, fractures, and rheumatic diseases.
• The Bioval® system with four bone-inserted sensors measured kinematic data during 1st MTPJ manipulation.

Main Results:

• A direct correlation was observed between 1st MTPJ extension-plantar flexion and femur rotation at 45° extension.
• Maximal 1st MTPJ extension showed a direct relationship with 1st metatarsal plantar flexion and prono-supination, as well as tibia and femur rotation.

Conclusions:

• Increased 1st MTPJ extension degree correlates with greater generated leg movement.
• This increased movement may reduce impact on distal structures, affecting the entire leg.
• The study's kinematic system limitations prevented precise quantification of the impact.