Ankle and Plantar Flexor Muscle-Tendon Unit Function in Sprinters: A Narrative Review

Area of Science:

• Biomechanics
• Human Movement Science
• Sports Physiology

Background:

• Maximal sprinting performance relies on coordinated muscle-tendon unit (MTU) and joint function.
• The plantar flexor MTU and ankle joint are critical for ground force application during sprinting.
• Understanding their roles across different sprint phases is key to optimizing performance.

Purpose of the Study:

• To review the contribution of the ankle joint and plantar flexor MTUs during sprint start, acceleration, and maximum velocity phases.
• To examine musculotendinous properties enhancing plantar flexor MTU performance.
• To identify factors contributing to elite sprint performance related to ankle and plantar flexor function.

Main Methods:

• Narrative review of existing literature on sprinting biomechanics.
• Analysis of the role of the ankle joint and plantar flexor MTUs in different sprint phases.
• Comparison of physiological and biomechanical characteristics between elite and sub-elite sprinters.

Main Results:

• The rear leg ankle joint and plantar flexor MTU's stretch-shortening cycle (SSC) are vital for sprint starts.
• Elite sprinters exhibit higher rate of force development (RFD) and horizontal block power, transferred via the ankle.
• During acceleration, the ankle and plantar flexor MTU are critical, with distinct roles for soleus (support) and gastrocnemius (propulsion/support).
• At maximum velocity, the ankle joint dissipates energy but is essential for transferring power to the ground.

Conclusions:

• The ankle joint and plantar flexor MTUs are indispensable throughout all sprinting phases.
• Elite sprinters possess superior RFD and power transfer capabilities through the ankle.
• Optimal plantar flexor MTU characteristics, potentially influenced by footwear and technique, are crucial for peak performance.