Muscle-Tendon Mechanics and Adaptation

Muscle–tendon units form an integrated system that transmits contractile force from muscle fibres to the skeleton, enabling movement, posture and energy exchange. Tendons, composed primarily of collagen and organised into hierarchical structures, exhibit elastic behaviour that permits storage and release of strain energy. This interplay reduces metabolic cost and modulates force output during dynamic activities such as walking, running and jumping. Adaptation arises through changes in tendon stiffness, cross-sectional area and material properties in response to mechanical loading, ageing or disuse. Concurrently, muscle architecture—including fibre length, pennation angle and aponeurosis geometry—adjusts to optimise force–length–velocity characteristics. Advances in imaging, modelling and wearable sensing have revealed the heterogeneity of aponeuroses and tendons, the sex-specific responses to training, and the nonlinear mechanics underlying injury risk and rehabilitation outcomes. Understanding these mechanisms is vital for injury prevention, performance enhancement and clinical treatments of musculoskeletal disorders.

Research from Nature Portfolio

Recent studies have introduced a non-invasive shear wave tensiometer to quantify in vivo tendon loading by tracking the speed of induced vibrational waves. This approach demonstrates that shear wave velocity correlates with axial stress in human Achilles and patellar tendons, modulating in phase with joint torque during isometric contractions, walking and running. The technique offers a direct measure of muscle–tendon forces without invasive procedures or extensive modelling assumptions, paving the way for improved motor control analysis and personalised rehabilitation strategies.

Muscle-Tendon Mechanics and Adaptation publication trend

The graph below shows the total number of articles in muscle-tendon mechanics and adaptation across all publications each year (not limited to Nature Index journals).

Technical terms

Muscle–tendon unit: The functional complex of muscle fibres, aponeuroses and tendon that transmits contractile force to the skeleton.

Aponeurosis: A sheet-like connective tissue that connects muscle fibres to tendon and contributes to force transmission and elastic storage.

Shear wave tensiometer: A sensor system that measures tendon stress by tracking the speed of mechanically induced shear waves along the tissue.

Stiffness: The resistance of a tendon or aponeurosis to deformation under load, often quantified as the slope of the force–elongation curve.

Strain: The relative change in length of a material (tendon or aponeurosis) under applied stress, usually expressed as a percentage.

References

1. More than energy cost: multiple benefits of the long Achilles tendon in human walking and running. Biological Reviews (2023).
2. Wearable approaches for non-invasive monitoring of tendons: A scoping review. Internet of Things (2024).
3. Female Tendons are from Venus and Male Tendons are from Mars, But Does it Matter for Tendon Health?. Sports Medicine (2024).
4. Aponeurosis structure-function properties: Evidence of heterogeneity and implications for muscle function. Acta Biomaterialia (2023).
5. Gauging force by tapping tendons. Nature Communications (2018).