Age-related differences in the properties of the plantar flexor muscles and tendons

Kubo, Keitaro<sup>1</sup>; Morimoto, Masanori<sup>2</sup>; Komuro, Teruaki<sup>2</sup>; Tsunoda, Naoya<sup>2</sup>; Kanehisa, Hiroaki<sup>1</sup>; Fukunaga, Tetsu<sup>3</sup>

Affiliations

¹Department of Life Science, University of Tokyo, Meguro, Tokyo, JAPAN

²Department of Physical Education, Kokushikan University, Tokyo, JAPAN

³Department of Sports Sciences, Waseda University, Tokorozawa, Saitama, JAPAN

Abstract and keywords

Purpose: The purpose of this study was to determine age-related differences in the human plantar flexor muscles and tendon.

Methods: Four age groups-a 20-yr group (20-27 yr, N = 19), 30-yr group (31-38 yr, N = 15), 50-yr group (46-57 yr, N = 10) and 70-yr group (62-77 yr, N = 15)-volunteered to take part in the present study. Muscle thickness, strength, and activation level (using twitch-interpolation technique) of plantar flexor muscles were measured. Elongation of the Achilles tendon was determined using ultrasonography while subjects performed ramp isometric plantar flexion up to the voluntary maximum.

Results: No significant difference in relative muscle thickness (to limb length) was observed among the four age groups. Muscle strength and activation level of the 20-yr group were significantly higher than those of the 50- and 70-yr groups (activation levels were not measured in the 70-yr group), and maximal strain (elongation/initial tendon length) of the Achilles tendon decreased with aging. Although there were no differences in muscle strength and activation levels between the 20- and 30-yr groups, maximal strain of the Achilles tendon of the 30-yr group was already lower than that of the 20-yr group (P = 0.062).

Conclusion: These results suggest that the processes of age-related changes in the muscle and tendon are different. Furthermore, the differences in age-related changes of muscle and tendon might play a role in the frequency of Achilles tendon ruptures among men in their 30s.

Keywords: tendon; elongation; aging; ultrasonography; muscle

Links

DOI: 10.1249/01.mss.0000247006.24965.74

PubMed: 17473781

WoS: 000245084500018

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Cited By (4)

Year	Entry
2010	Chao CYL, Zheng Y-P, Huang Y-P, Cheing GLY. Biomechanical properties of the forefoot plantar soft tissue as measured by an optical coherence tomography-based air-jet indentation system and tissue ultrasound palpation system. Clin Biomech (Bristol, Avon). 2010;25(6):594-600.
2011	Neugebauer JM. Factors Related to Achilles Tendon Mechanical Properties and Loading During Locomotion in Growing Youth: Implications for Biomechanically Based Physical Activity Guidelines [PhD thesis]. Davis, University of California; 2011.
2011	Ferreira LM. Development of an Active Elbow Motion Simulator and Coordinate Systems to Evaluate Kinematics in Multiple Positions [PhD thesis]. University of Western Ontario; 2011.
2014	Slane LC. Achilles Tendon Elasticity and Deformation Patterns in Young and Middle-Aged Adults Evaluated Using Quantitative Ultrasound Approaches [PhD thesis]. University of Wisconsin – Madison; 2014.