Human tendon behaviour and adaptation, in vivo.

Area of Science:

• Biomechanics
• Human Physiology
• Musculoskeletal System

Background:

• Tendon properties are vital for joint movement, involving complex interactions between the nervous system, muscles, and bones.
• Limited in vivo data on human tendons historically hindered understanding, but new methods offer fresh insights.

Purpose of the Study:

• To review advancements in understanding human tendon and aponeurosis function in vivo.
• To explore tendon adaptations to aging, loading, and unloading conditions.

Main Methods:

• Review of recent in vivo studies on human tendon and aponeurosis.
• Analysis of experimental evidence on tendon metabolic activity and mechanical properties.

Main Results:

• Tendons undergo significant length changes during passive and active loading, storing elastic energy.
• The Achilles tendon provides elastic energy during walking, reducing locomotion costs.
• Human tendons exhibit high metabolic activity, enabling adaptation to changing demands.
• Aging and disuse reduce tendon stiffness, which resistance exercise can mitigate.

Conclusions:

• Tendon's elastic properties are key to locomotion efficiency.
• High metabolic activity supports tendon adaptation.
• Resistance exercise can counteract age-related stiffness reduction, benefiting movement and injury prevention.