|
| |
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
First published online December 2, 2005
Journal of Experimental Biology 208, 4715-4725 (2005)
Published by The Company of Biologists 2005
doi: 10.1242/jeb.01950
In vivo mechanical properties of the human Achilles tendon during one-legged hopping
1 Structure and Motion Laboratory, Institute of Orthopaedics and
Musculoskeletal Sciences, University College London, Royal National
Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex, HA7 4LP,
UK
2 Structure and Motion Laboratory, The Royal Veterinary College, Hawkshead
Lane, North Mymms, Hatfield, Herts, AL9 7TA, UK
* Author for correspondence (e-mail: g.lichtwark{at}ucl.ac.uk)
Accepted 25 October 2005
Compliant tendons act as energy stores, which benefit the energetics and power output of a muscle–tendon unit. However the compliance of tendon and the material properties may vary between individuals and hence alter the energy storing capacity of the tendon. We aimed to determine the in vivo Achilles tendon (AT) stress and strain during one-legged hopping and hence the contribution of elastic recoil to mechanical energy changes. We simultaneously measured the length of the Achilles tendon from the muscle–tendon junction to the insertion on the calcaneous and the approximate AT force in ten male participants. The position of the muscle–tendon junction was determined using ultrasound images that were projected into three-dimensional space. Achilles tendon force was measured using inverse dynamics. The results demonstrated that one-legged hopping elicited high tendon strains and that the force–length relationship of the whole tendon is relatively linear, particularly at high strains. The stiffness, elastic modulus and hysteresis varied across the population (inter-quartile range of 145–231 N mm–1, 0.67–1.07 GPa and 17–35%, respectively). These values are within the reported biological range. An average of 38 J of energy was recovered from the elastic recoil of the tendon, which contributes 16% of the total average mechanical work of the hop (254 J). The high strains measured here (average peak strain was 8.3%) and in other studies may be possible due to the complex architecture of the Achilles tendon; however, prolonged hopping may well cause tendon damage. In conclusion, the properties of the elastic Achilles tendon can contribute significantly to the total mechanical work of the body during one-legged hopping; however, individual variation in the properties of the tendon vary the energy storing capacity of this structure.
Key words: elasticity, biomechanics, stress, strain, elastic modulus, human
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati 
Twitter What's this?
This article has been cited by other articles:
|
|
 |
|
  A. M. Grabowski and H. M. Herr Leg exoskeleton reduces the metabolic cost of human hopping J Appl Physiol, September 1, 2009; 107(3): 670 - 678. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. D. Rees, G. A. Lichtwark, R. L. Wolman, and A. M. Wilson The mechanism for efficacy of eccentric loading in Achilles tendon injury; an in vivo study in humans Rheumatology, October 1, 2008; 47(10): 1493 - 1497. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. A. Lichtwark and A. M. Wilson Interactions between the human gastrocnemius muscle and the Achilles tendon during incline, level and decline locomotion J. Exp. Biol., November 1, 2006; 209(21): 4379 - 4388. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. E. Vereecke, K. D'Aout, and P. Aerts The dynamics of hylobatid bipedalism: evidence for an energy-saving mechanism? J. Exp. Biol., August 1, 2006; 209(15): 2829 - 2838. [Abstract] [Full Text] [PDF]
|
|
