European Journal of Applied Physiology

, Volume 114, Issue 1, pp 59–69 | Cite as

The influence of loading intensity on muscle–tendon unit behavior during maximal knee extensor stretch shortening cycle exercise

  • Jacob E. Earp
  • Robert U. Newton
  • Prue Cormie
  • Anthony J. Blazevich
Original Article


Tendon stiffness increases as the magnitude and rate of loading increases, according to its viscoelastic properties. Thus, under some loading conditions tendons should become exceptionally stiff and act almost as rigid force transducers. Nonetheless, observations of tendon behavior during multi-joint sprinting and jumping tasks have shown that tendon strain increases whilst muscle strain decreases as the loading intensity increases. The purpose of the current study was to examine the influence of external loading intensity on muscle–tendon unit (MTU) behavior during a high-speed single-joint, stretch-shortening cycle (SSC) knee extension task. Eighteen men (n = 9) and women (n = 9) performed single-leg, maximum intensity SSC knee extensions at loads of 20, 60 and 90 % of their one repetition maximum. Vastus lateralis fascicle length (L f) and velocity (v f) as well as MTU (L MTU) and tendinous tissue (L t) length were measured using high-speed ultrasonography (96 Hz). Patellar tendon force (F t) and rate of force development (RFDt) were estimated using inverse dynamics. Results showed that as loading intensity increased, concentric joint velocity and shortening v f decreased whilst F t and RFDt increased, but no significant differences were observed in eccentric joint velocity or peak L MTU or L f. In addition, the tendon lengthened significantly less at the end of the eccentric phase at heavier loads. This is the first observation that tendon strain decreases significantly during a SSC movement as loading intensity increases in vivo, resulting in a shift in the tendon acting as a power amplifier at light loads to a more rigid force transducer at heavy loads.


Viscoelastic Fascicle Rate of force development Quadriceps tendon Patellar tendon 


  1. Abellaneda S, Guissard N, Duchateau J (2009) The relative lengthening of the myotendinous structures in the medial gastrocnemius during passive stretching differs among individuals. J Appl Phys 106:169–177Google Scholar
  2. Baratta R (1991) The effect of tendon viscoelastic stiffness on the dynamic performance of isometric muscle. J Biomech 24:109–116PubMedCrossRefGoogle Scholar
  3. Bobbert M (2001) Dependence of human squat jump performance on the series elastic compliance of the triceps surae: a simulation study. J Exp Biol 533:533–543Google Scholar
  4. Bobbert M, Ettema G, Huijing P (1990) The force–length relationship of a muscle–tendon complex: experimental results and model calculations. Euro J Appl Physiol O 61:323–329CrossRefGoogle Scholar
  5. Cormie P, McBride J, McCaulley G (2008) Power–time, force–time, and velocity–time curve analysis during the jump squat: impact of load. J Appl Biom 24:112–120Google Scholar
  6. Earp J, Cormie P, Newton R (2013) Knee angle-specific EMG normalization: the use of polynomial based EMG–angle relationships. J Electromyogr Kinesiol 23:238–244Google Scholar
  7. Ettema G (1996) Mechanical efficiency and efficiency of storage and release of series elastic energy in skeletal muscle during stretch–shorten cycles. J Exp Biol 199:1983–1997PubMedGoogle Scholar
  8. Ettema G, Huijing P (1994) Skeletal muscle stiffness in static and dynamic contractions. J Biom 27:1361–1368CrossRefGoogle Scholar
  9. Finni T (2006) Structural and functional features of human muscle–tendon unit. Scand J Med Sci Spor 16:147–158CrossRefGoogle Scholar
  10. Finni T, Ikegawa S, Lepola V, Komi P (2001) In vivo behavior of vastus lateralis muscle during dynamic performances. E J Sport Sci 1:1–13CrossRefGoogle Scholar
  11. Finni T, Ikegawa S, Lepola V, Komi P (2003) Comparison of force–velocity relationships of vastus lateralis muscle in isokinetic and in stretch–shortening cycle exercises. Acta Physiol Scand 177:483–491PubMedCrossRefGoogle Scholar
  12. Fukunaga T, Kawakami Y, Kubo K, Kanehisa H (2002) Muscle and tendon interaction during human movements. Exerc Sport Sci R 30:106–110CrossRefGoogle Scholar
  13. Hawkins D, Hull M (1990) A method for determining lower extremity muscle–tendon lengths during flexion/extension movements. J Biomech 23:7CrossRefGoogle Scholar
  14. Hermie JH (1996) The state of the art on sensors and sensor placement procedures for surface electromyography: a proposal for sensor placement procedures. Roessingh R&D, NetherlandsGoogle Scholar
  15. Ishikawa M, Komi P (2004) Effects of different dropping intensities on fascicle and tendinous tissue behavior during stretch–shortening cycle exercise. J Appl Phys 96:848–852Google Scholar
  16. Ishikawa M, Komi P (2007) The role of the stretch reflex in the gastrocnemius muscle during human locomotion at various speeds. J Appl Phys 103:1030–1036Google Scholar
  17. Ishikawa M, Finni T, Komi P (2003) Behaviour of vastus lateralis muscle tendon during high intensity SSC exercises in vivo. Acta Physiol Scand 178:205–213PubMedCrossRefGoogle Scholar
  18. Ishikawa M, Niemela E, Komi P (2005) Interaction between fascicle and tendinous tissues in short-contact stretch–shortening cycle exercise with varying eccentric intensities. J Appl Phys 99:217–223Google Scholar
  19. Ishikawa M, Komi P, Finni T, Kuitunen S (2006) Contribution of the tendinous tissue to force enhancement during stretch shortening cycle exercise depends on the prestretch and concentric phase intensities. J Electromyogr Kinesiol 16:423–431PubMedCrossRefGoogle Scholar
  20. Ishikawa M, Pakaslahti J, Komi P (2007) Medial gastrocnemius muscle behavior during human running and walking. Gait Posture 25:380–384PubMedCrossRefGoogle Scholar
  21. Ito M, Kawakami Y, Ichinose Y, Fukashiro S, Fukunaga T (1998) Nonisometric behavior of fascicles during isometric contractions of a human muscle. J Appl Phys 85:1230–1235Google Scholar
  22. Kubo K, Kawakami Y, Fukunaga T (1999) Influence of elastic properties of tendon structures on jump performance in humans. J Appl Phys 87:2090–2096Google Scholar
  23. Kubo K, Kanehisa H, Fukunaga T (2005) Effects of viscoelastic properties of tendon structures on stretch shortening cycle exercise in vivo. J Sports Sci 23:851–860PubMedCrossRefGoogle Scholar
  24. Kubo K, Morimoto M, Komuro T, Tsunoda N, Kanehisa H, Fukunaga T (2007) Influences of tendon stiffness, joint stiffness, and electromyographic activity on jump performances using single joint. Euro J Appl Physiol 99:235–243CrossRefGoogle Scholar
  25. Kurokawa S, Fukunaga T, Fukashiro S (2001) Behavior of fascicles and tendinous structures of human gastrocnemius during vertical jumping. J Appl Phys 90:1349–1358Google Scholar
  26. Magnusson S, Narici M, Maganaris C, Kjaer M (2008) Human tendon behaviour and adaptation, in vivo. J Physiol 586:71–81PubMedCrossRefGoogle Scholar
  27. Nagano A, Komura T, Fukashiro S (2004) Effects of the length ratio between the contractile element and the series elastic element on an explosive muscular performance. J Electromyogr Kinesiol 14:197–203PubMedCrossRefGoogle Scholar
  28. Netti P, Ronca D, Ambrosio L, Nicolais L (1996) Structure–mechanical properties relationship of natural tendon and ligaments. J Mater Sci 7:525–530Google Scholar
  29. Reeves N, Narici M (2003) Behavior of human muscles fascicles during shortening and lengthening contractions in vivo. J Appl Biom 95:1090–1097Google Scholar
  30. Roberts T (2002) The integrated function of muscles and tendons during locomotion. Comp Biochem Physiol A 133:1087–1099CrossRefGoogle Scholar
  31. Roeleveld K, Baratta R, Solomonow M, Van Soest A, Huijing P (1993) Role of tendon properties on the dynamic performance of different isometric muscles. J Appl Phys 74:1348–1355Google Scholar
  32. Sousa F, Ishikawa M, Vilas-Boas J, Komi P (2007) Intensity- and muscle-specific fascicle behavior during human drop jumps. J Appl Phys 102:382–389CrossRefGoogle Scholar
  33. Van Ingen Schenau G, Bobbert M, Haan A (1997) Does elastic energy enhance work and efficiency in the stretch–shortening cycle? J Appl Biom 13:389–415Google Scholar
  34. Van Soest A, Huijing P, Solomonow M (1995) The effect of tendon on muscle force in dynamic isometric contractions, a simulation study. J Biomech 28:801–807PubMedCrossRefGoogle Scholar
  35. Visser H, Bobbert M, Huijing P (1990) Length and moment arm of human leg muscles as a function of knee and hip-joint angles. Eur J Appl Physiol 61:7CrossRefGoogle Scholar
  36. Winter D (1990) Biomechanics and motor control of human movement. Wiley, TorontoGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Jacob E. Earp
    • 1
    • 2
  • Robert U. Newton
    • 2
  • Prue Cormie
    • 2
  • Anthony J. Blazevich
    • 2
  1. 1.Department of Movement Science, Sport and Leisure StudiesWestfield State UniversityWestfieldUSA
  2. 2.Centre for Exercise and Sports Science Research, School of Exercise and Health SciencesEdith Cowan UniversityJoondalupAustralia

Personalised recommendations