Differential strain patterns of the human gastrocnemius aponeurosis and free tendon, in vivo

S P Magnusson, P Hansen, P Aagaard, J Brønd, P Dyhre-Poulsen, J Bojsen-Moller, Michael Kjær

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

AIM: The mechanical characteristics of the human free tendon and aponeurosis, in vivo, remains largely unknown. The present study evaluated the longitudinal displacement of the separate free Achilles tendon and distal (deep) aponeurosis of the medial gastrocnemius muscle during voluntary isometric contraction.

METHODS: Ultrasonography-obtained displacement of the free tendon and tendon-aponeurosis complex, electromyography of the gastrocnemius, soleus, and dorsiflexor muscles, and joint angular rotation were recorded during isometric plantarflexion (n = 5). Tendon cross-sectional area, moment arm and segment lengths (L(o)) were measured using magnetic resonance imaging. Tendon force was calculated from joint moments and tendon moment arm, and stress was obtained by dividing force by cross-sectional area. The difference between the free tendon and tendon-aponeurosis complex deformation yielded separate distal aponeurosis deformation. Longitudinal aponeurosis and tendon strain were obtained from the deformations normalized to segment lengths.

RESULTS: At a common tendon force of 2641 +/- 306 N, the respective deformation and Lo were 5.85 +/- 0.85 and 74 +/- 0.8 mm for the free tendon and 2.12 +/- 0.64 and 145 +/- 1.3 mm for the distal aponeurosis, P < 0.05. Longitudinal strain was 8.0 +/- 1.2% for the tendon and 1.4 +/- 0.4% for the aponeurosis, P < 0.01. Stiffness and stored energy was 759 +/- 132 N mm(-1) and 6.14 +/- 1.89 J, respectively, for the free tendon. Cross-sectional area of the Achilles tendon was 73 +/- 4 mm2, yielding a stress of 36.5 +/- 4.6 MPa and Young's modulus of 788 +/- 181 MPa.

CONCLUSION: The free Achilles tendon demonstrates greater strain compared with that of the distal (deep) aponeurosis during voluntary isometric contraction, which suggests that separate functional roles may exist during in vivo force transmission.

Original languageEnglish
JournalActa Physiologica Scandinavica
Volume177
Issue number2
Pages (from-to)185-95
ISSN0001-6772
DOIs
Publication statusPublished - Feb 2003

Fingerprint

Achilles Tendon
Isometric Contraction
Skeletal Muscle
Joints
Elastic Modulus
Electromyography
Longitudinal Studies
Ultrasonography

Keywords

  • Achilles Tendon/anatomy & histology
  • Adult
  • Electromyography
  • Humans
  • Isometric Contraction/physiology
  • Magnetic Resonance Imaging
  • Male
  • Movement/physiology
  • Muscle, Skeletal/diagnostic imaging
  • Rotation
  • Stress, Mechanical
  • Ultrasonography

Cite this

@article{27f233735e354c699086c49852e1a2d5,
title = "Differential strain patterns of the human gastrocnemius aponeurosis and free tendon, in vivo",
abstract = "AIM: The mechanical characteristics of the human free tendon and aponeurosis, in vivo, remains largely unknown. The present study evaluated the longitudinal displacement of the separate free Achilles tendon and distal (deep) aponeurosis of the medial gastrocnemius muscle during voluntary isometric contraction.METHODS: Ultrasonography-obtained displacement of the free tendon and tendon-aponeurosis complex, electromyography of the gastrocnemius, soleus, and dorsiflexor muscles, and joint angular rotation were recorded during isometric plantarflexion (n = 5). Tendon cross-sectional area, moment arm and segment lengths (L(o)) were measured using magnetic resonance imaging. Tendon force was calculated from joint moments and tendon moment arm, and stress was obtained by dividing force by cross-sectional area. The difference between the free tendon and tendon-aponeurosis complex deformation yielded separate distal aponeurosis deformation. Longitudinal aponeurosis and tendon strain were obtained from the deformations normalized to segment lengths.RESULTS: At a common tendon force of 2641 +/- 306 N, the respective deformation and Lo were 5.85 +/- 0.85 and 74 +/- 0.8 mm for the free tendon and 2.12 +/- 0.64 and 145 +/- 1.3 mm for the distal aponeurosis, P < 0.05. Longitudinal strain was 8.0 +/- 1.2{\%} for the tendon and 1.4 +/- 0.4{\%} for the aponeurosis, P < 0.01. Stiffness and stored energy was 759 +/- 132 N mm(-1) and 6.14 +/- 1.89 J, respectively, for the free tendon. Cross-sectional area of the Achilles tendon was 73 +/- 4 mm2, yielding a stress of 36.5 +/- 4.6 MPa and Young's modulus of 788 +/- 181 MPa.CONCLUSION: The free Achilles tendon demonstrates greater strain compared with that of the distal (deep) aponeurosis during voluntary isometric contraction, which suggests that separate functional roles may exist during in vivo force transmission.",
keywords = "Achilles Tendon/anatomy & histology, Adult, Electromyography, Humans, Isometric Contraction/physiology, Magnetic Resonance Imaging, Male, Movement/physiology, Muscle, Skeletal/diagnostic imaging, Rotation, Stress, Mechanical, Ultrasonography",
author = "Magnusson, {S P} and P Hansen and P Aagaard and J Br{\o}nd and P Dyhre-Poulsen and J Bojsen-Moller and Michael Kj{\ae}r",
year = "2003",
month = "2",
doi = "10.1046/j.1365-201X.2003.01048.x",
language = "English",
volume = "177",
pages = "185--95",
journal = "Acta Physiologica Scandinavica",
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}

Differential strain patterns of the human gastrocnemius aponeurosis and free tendon, in vivo. / Magnusson, S P; Hansen, P; Aagaard, P; Brønd, J; Dyhre-Poulsen, P; Bojsen-Moller, J; Kjær, Michael.

In: Acta Physiologica Scandinavica, Vol. 177, No. 2, 02.2003, p. 185-95.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Differential strain patterns of the human gastrocnemius aponeurosis and free tendon, in vivo

AU - Magnusson, S P

AU - Hansen, P

AU - Aagaard, P

AU - Brønd, J

AU - Dyhre-Poulsen, P

AU - Bojsen-Moller, J

AU - Kjær, Michael

PY - 2003/2

Y1 - 2003/2

N2 - AIM: The mechanical characteristics of the human free tendon and aponeurosis, in vivo, remains largely unknown. The present study evaluated the longitudinal displacement of the separate free Achilles tendon and distal (deep) aponeurosis of the medial gastrocnemius muscle during voluntary isometric contraction.METHODS: Ultrasonography-obtained displacement of the free tendon and tendon-aponeurosis complex, electromyography of the gastrocnemius, soleus, and dorsiflexor muscles, and joint angular rotation were recorded during isometric plantarflexion (n = 5). Tendon cross-sectional area, moment arm and segment lengths (L(o)) were measured using magnetic resonance imaging. Tendon force was calculated from joint moments and tendon moment arm, and stress was obtained by dividing force by cross-sectional area. The difference between the free tendon and tendon-aponeurosis complex deformation yielded separate distal aponeurosis deformation. Longitudinal aponeurosis and tendon strain were obtained from the deformations normalized to segment lengths.RESULTS: At a common tendon force of 2641 +/- 306 N, the respective deformation and Lo were 5.85 +/- 0.85 and 74 +/- 0.8 mm for the free tendon and 2.12 +/- 0.64 and 145 +/- 1.3 mm for the distal aponeurosis, P < 0.05. Longitudinal strain was 8.0 +/- 1.2% for the tendon and 1.4 +/- 0.4% for the aponeurosis, P < 0.01. Stiffness and stored energy was 759 +/- 132 N mm(-1) and 6.14 +/- 1.89 J, respectively, for the free tendon. Cross-sectional area of the Achilles tendon was 73 +/- 4 mm2, yielding a stress of 36.5 +/- 4.6 MPa and Young's modulus of 788 +/- 181 MPa.CONCLUSION: The free Achilles tendon demonstrates greater strain compared with that of the distal (deep) aponeurosis during voluntary isometric contraction, which suggests that separate functional roles may exist during in vivo force transmission.

AB - AIM: The mechanical characteristics of the human free tendon and aponeurosis, in vivo, remains largely unknown. The present study evaluated the longitudinal displacement of the separate free Achilles tendon and distal (deep) aponeurosis of the medial gastrocnemius muscle during voluntary isometric contraction.METHODS: Ultrasonography-obtained displacement of the free tendon and tendon-aponeurosis complex, electromyography of the gastrocnemius, soleus, and dorsiflexor muscles, and joint angular rotation were recorded during isometric plantarflexion (n = 5). Tendon cross-sectional area, moment arm and segment lengths (L(o)) were measured using magnetic resonance imaging. Tendon force was calculated from joint moments and tendon moment arm, and stress was obtained by dividing force by cross-sectional area. The difference between the free tendon and tendon-aponeurosis complex deformation yielded separate distal aponeurosis deformation. Longitudinal aponeurosis and tendon strain were obtained from the deformations normalized to segment lengths.RESULTS: At a common tendon force of 2641 +/- 306 N, the respective deformation and Lo were 5.85 +/- 0.85 and 74 +/- 0.8 mm for the free tendon and 2.12 +/- 0.64 and 145 +/- 1.3 mm for the distal aponeurosis, P < 0.05. Longitudinal strain was 8.0 +/- 1.2% for the tendon and 1.4 +/- 0.4% for the aponeurosis, P < 0.01. Stiffness and stored energy was 759 +/- 132 N mm(-1) and 6.14 +/- 1.89 J, respectively, for the free tendon. Cross-sectional area of the Achilles tendon was 73 +/- 4 mm2, yielding a stress of 36.5 +/- 4.6 MPa and Young's modulus of 788 +/- 181 MPa.CONCLUSION: The free Achilles tendon demonstrates greater strain compared with that of the distal (deep) aponeurosis during voluntary isometric contraction, which suggests that separate functional roles may exist during in vivo force transmission.

KW - Achilles Tendon/anatomy & histology

KW - Adult

KW - Electromyography

KW - Humans

KW - Isometric Contraction/physiology

KW - Magnetic Resonance Imaging

KW - Male

KW - Movement/physiology

KW - Muscle, Skeletal/diagnostic imaging

KW - Rotation

KW - Stress, Mechanical

KW - Ultrasonography

U2 - 10.1046/j.1365-201X.2003.01048.x

DO - 10.1046/j.1365-201X.2003.01048.x

M3 - Journal article

C2 - 12558555

VL - 177

SP - 185

EP - 195

JO - Acta Physiologica Scandinavica

JF - Acta Physiologica Scandinavica

SN - 0001-6772

IS - 2

ER -