Shank Muscle Strength Training Changes Foot Behaviour during a Sudden Ankle Supination

Area of Science:

• Biomechanics
• Sports Science
• Anatomy

Background:

• Peroneal muscles are key lateral stabilizers of the ankle complex.
• Excessive supination can lead to ankle injuries.
• Machine-based training offers a structured approach to strengthening shank muscles.

Purpose of the Study:

• To investigate the morphological and biomechanical effects of two distinct machine-based shank muscle training methods.
• To compare the efficacy of subtalar pronator/supinator training (ST) versus talocrural plantar and dorsiflexor training (TT).

Main Methods:

• Twenty-two healthy male students underwent 10 weeks of high-resistance strength training (3 sessions/week).
• One leg received ST using a custom apparatus; the other received TT.
• Evaluated muscle strength (MVIC), muscle volume, and foot biomechanics during sudden ankle supination.

Main Results:

• ST yielded significantly greater increases in pronator (14%) and supinator (25%) MVIC compared to TT (8% and 12%, respectively).
• Both ST and TT reduced supination velocity by 12% during sudden inversions.
• Muscle reaction onset time for peroneus longus (PL) improved, and muscle volume of PL and tibialis anterior (TA) increased significantly with both training types.

Conclusions:

• Both ST and TT enhance ankle joint complex mechanical stability against sudden supination, primarily due to increased muscle volume in PL and TA.
• Strength training benefits, including reduced supination velocity, are evident even during dynamic movements like free-fall.
• Machine-based training targeting dorsiflexors and pronators is recommended for improving ankle mechanical stability.