The Mechanisms Leading to Tendon Lengthening and Tendon Strength-Recovery Deficiency during Achilles Tendon Healing Process

Komeno M, Yamazaki S, et al.

Journal of the Japanese Society of Physical Therapy Fundamentals

Saitama Prefectural University, Japan Society for the Promotion of Science (JSPS)

RESEARCH SUMMARY

This study investigated the biomechanical and morphological mechanisms underlying tendon lengthening and incomplete recovery of tensile strength during the Achilles tendon healing process in a murine model. The researchers analyzed temporal changes in tendon stiffness, cross-sectional area, and collagen alignment following surgical injury and subsequent healing. Despite progressive tissue regeneration, mechanical testing revealed residual deficits in tensile strength and elastic modulus, suggesting structural remodeling and collagen disorganization as key contributors to prolonged weakness post-healing. The findings provide mechanistic insight into tendon elongation and the delayed recovery of mechanical properties relevant to rehabilitation.

Tensile mechanical testing of healing mouse Achilles tendons was performed using a CellScale UniVert mechanical testing system (Waterloo, ON, Canada). Tendon specimens were mounted and subjected to uniaxial tension at controlled strain rates until failure. Force–displacement data were used to calculate ultimate load, stress, and Young’s modulus, revealing that healed tendons exhibited significantly lower maximum stress and stiffness compared to uninjured controls. The UniVert results quantitatively demonstrated tendon elongation and mechanical recovery deficiency during the healing process.

AUTHORS

Moe Komeno, Saki Yamazaki, Takumi Umehara, Akihiro Kubo, Yuki Takehara, Shunsuke Sano, Daisuke Ikeda.

PUBLICATION DETAILS

JOURNAL

Journal of the Japanese Society of Physical Therapy Fundamentals

YEAR

2025

INSTITUTIONS

Saitama Prefectural University, Japan Society for the Promotion of Science (JSPS)

COUNTRIES

Japan

INSTRUMENT USED

UniVert

TESTING METHODS

Hydrated and Temperature Controlled TestingMicro-Mechanical TestingTensile Testing

RESEARCH APPLICATIONS

Fibrosis & Tissue RemodelingMechanotransductionMusculoskeletal Tissue Engineering & MechanicsTendon Tissue Engineering & Ligament Mechanics

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