Achilles Tendon Load is Progressively Increased with Reductions in Walking Speed

Area of Science:

• Biomechanics
• Musculoskeletal rehabilitation
• Orthopedics

Background:

• Achilles tendon rehabilitation often involves gradually increasing walking speed.
• This approach aims to progressively increase mechanical loading on the tendon.
• The direct impact of walking speed on Achilles tendon loading in vivo is not fully understood.

Purpose of the Study:

• To investigate the influence of walking speed on Achilles tendon loading.
• To evaluate the relationship between walking speed and ultrasound transmission velocity in the Achilles tendon.
• To assess the implications for current rehabilitation strategies.

Main Methods:

• Transmission-mode ultrasound measured axial transmission speed in the Achilles tendon of 33 adults.
• Measurements were taken during treadmill walking at slow, preferred, and fast speeds.
• Ankle kinematics, gait parameters, and ground reaction forces were simultaneously recorded.

Main Results:

• Higher walking speeds correlated with increased cadence, step length, ankle plantarflexion, and ground reaction forces.
• Achilles tendon ultrasound transmission velocity significantly decreased during the stance phase with increasing walking speed.
• This reduction in velocity was observed at speeds between 16-23 m/s.

Conclusions:

• Increased walking speed leads to reduced Achilles tendon tensile load, indicated by decreased ultrasound transmission velocity.
• Current rehabilitation protocols advocating slower speeds early on may not align with these findings.
• The study suggests a re-evaluation of progressive loading strategies for Achilles tendon injuries based on walking speed.