The effects of exercise on tendon properties

1
The effects of exercise on tendon properties

• Structural, mechanical, and biochemical
  adaptations

2
Exercise and Tendons

• Training leads to increased force production in
  muscles
• Tendons, which transmit these forces should adapt
  to the new loads as well
• What kind of adaptations occur?
• Increased strength, stiffness?
• Greater collagen quantity, organization?

3
Outline

• Tendon Structure and Function
• Tendon Response to Exercise
• Collagen synthesis in response to acute
  mechanical loading
• Interpretation
• Further research

4
Tendon Structure

• Tendons are organized hierarchically
• Composed primarily of Type I collagen
• Also contain Type III collagen, proteoglycans,
  elastin and other proteins

5
Tendon Function

• Tendons transmit, store and dissipate energy
• Strength Maximum stress before failure
• Stiffness Deformation for a given force

6
Tendons Response to Exercise

• Various animal studies have demonstrated that
  exercise affects tendon strength, stiffness, size
  and biochemistry 1
• Human subject studies have shown improved tendon
  properties as well 3, 4
• Recent studies show gender has an affect on the
  tendons response to exercise 5, 6, 7

7
Collagen synthesis in response to acute
mechanical loading

• Subjects - 16 men and 16 women
• Exposure - 60 minute bout of one-legged kicking
  exercise at 67 workload maximum
• Outcome measure - Fractional synthesis rate (FSR)
  of collagen in the patellar tendon at rest and 72
  hrs after exercise
• FSR is a measure of new collagen production

Miller BF, et al. (2007) Tendon collagen
synthesis at rest and after exercise in women. J
Appl Physiol. Feb102(2)541-6.
8
Collagen synthesis in response to acute
mechanical loading

• Tendon collagen FSR is greater in men than women
• A 1 hr bout of exercise results in
• an increase in FSR in men
• No change in FSR in women

Miller BF, et al. (2007) Tendon collagen
synthesis at rest and after exercise in women. J
Appl Physiol. Feb102(2)541-6.
9
Interpretation of results

• A short exposure to exercise is enough to elicit
  an anabolic response in men
• This effect is not seen in women
• May be due to hormonal differences or mechanical
  force transmission
• This could explain why women are at greater risk
  for tendon injuries in sports

Miller BF, et al. (2007) Tendon collagen
synthesis at rest and after exercise in women. J
Appl Physiol. Feb102(2)541-6.
10
Future questions

• What other biochemical markers may indicate early
  tendon adaptation to exercise
• Collagen type (I vs III), elastin, proteoglycan
  content
• How do differences in exposure alter tendon
  adaptation
• Intensity, frequency, duration
• What is the underlying mechanism by which tendon
  adaptation is seen in men but not in women

11
References

• Buchanan, C.I., Marsh, R.L. (2002). Effects of
  exercise on the biomechanical, biochemical and
  structural properties of tendons. Comp Biochem
  Physiol A Mol Integr Physiol. Dec
  133(4)1101-7.
• Jozsa, L. and Kannus, P. (1997). Human Tendons
  Anatomy, Physiology and Pathology. Champaign,IL
  Human Kinetics.
• Kubo K, Kanehisa H, Ito M, Fukunaga T. (2001)
  Effects of isometric training on the elasticity
  of human tendon structures in vivo. J Appl
  Physiol. Jul 91(1)26-32.
• Kubo K, Yata H, Kanehisa H, Fukunaga T. (2006)
  Effects of isometric squat training on the
  tendon stiffness and jump performance. Eur J Appl
  Physiol. 2006 Feb 96(3)305-14.
• Miller, B.F., Hansen, M., Olesen, J.L., Schwarz,
  P., Babraj, J.A., Smith, K., et al. (2007).
  Tendon collagen synthesis at rest and after
  exercise in women. J Appl Physiol. Feb
  102(2)541-6.
• Miller, B.F., Olesen, J.L., Hansen, M., Døssing,
  S., Crameri, R.M., Welling, R.J., et al. (2005).
  Coordinated collagen and muscle protein synthesis
  in human patella tendon and quadriceps muscle
  after exercise. J Physiol. Sep 15 567(Pt
  3)1021-33.
• Westh, E., Kongsgaard, M., Bojsen-Moller, J.,
  Aagaard, P., Hansen, M., Kjaer, M., et al.
  (2008). Effect of habitual exercise on the
  structural and mechanical properties of human
  tendon, in vivo, in men and women. Scand J Med
  Sci Sports. Feb18(1)23-30.