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Tendons: What’s Load Got to Do With It? · MSKMag OutLoud

• 0:00
  SPEAKER_00: Tendons.
• 0:01
  SPEAKER_00: What's load got to do, got to do with it?
• 0:05
  SPEAKER_00: Written by Daniel Morgan.
• 0:07
  SPEAKER_00: Sorry about the singing.
• 0:09
  SPEAKER_00: Sponsored by Medimo.
• 0:11
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• 0:14
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• 0:15
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• 0:20
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• 0:24
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• 0:24
  SPEAKER_00: You just need to be a member.
• 0:27
  SPEAKER_00: Tendons are frequently discussed as though loading is either therapeutic or harmful.
• 0:32
  SPEAKER_00: That distinction is too simple.
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  SPEAKER_00: Mechanical loading is essential for tendon homeostasis,
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  SPEAKER_00: adaptation and performance,
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  SPEAKER_00: yet the same load may be tolerated by one athlete and provocative for another.
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  SPEAKER_00: The relevant question is therefore not whether a tendon should be loaded,
• 0:48
  SPEAKER_00: but whether the magnitude, rate,
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  SPEAKER_00: volume and frequency of loading are appropriate for its present capacity
• 0:54
  SPEAKER_00: and are followed by sufficient recovery.
• 0:58
  SPEAKER_00: The distinction is particularly important for the Achilles tendon.
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  SPEAKER_00: During locomotion,
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  SPEAKER_00: the Achilles transmits force from the gastrocnemius soleus complex and stores
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  SPEAKER_00: and returns elastic energy.
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  SPEAKER_00: Running,
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  SPEAKER_00: jumping,
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  SPEAKER_00: accelerating and changing direction expose it to substantial forces delivered
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  SPEAKER_00: over short time periods.
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  SPEAKER_00: Long-term preparation must develop the capacity to tolerate these demands.
• 1:22
  SPEAKER_00: Acute preparation immediately Tendon Structure, Function and Adaptation
• 1:48
  SPEAKER_00: Tendon is a hierarchical collagen-rich tissue rather than an inert cable.
• 1:54
  SPEAKER_00: Collagen molecules form fibrils, fibres and fascicles while the interfascicular
• 2:05
  SPEAKER_00: Matrix Interfascicular Matrix.
• 2:09
  SPEAKER_00: Sorry, I don't know if you pronounce that first C.
• 2:12
  SPEAKER_00: Matrix permits relative movement between these structures.
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  SPEAKER_00: Tenocytes and tendon derived cells respond to mechanical deformation
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  SPEAKER_00: through mechanotransduction.
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  SPEAKER_00: Mechanical signals are converted into cellular responses influencing collagen synthesis.
• 2:28
  SPEAKER_00: Extracellular matrix turnover and tendon mechanical properties.
• 2:33
  SPEAKER_00: Adaptation is therefore load dependent, but it is not determined by external weight alone.
• 2:38
  SPEAKER_00: Joint position,
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  SPEAKER_00: muscle recruitment,
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  SPEAKER_00: moment arm,
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  SPEAKER_00: contraction type,
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  SPEAKER_00: movement,
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  SPEAKER_00: velocity and individual anatomy all influence the force and strain experienced by
• 2:47
  SPEAKER_00: the tendon.
• 2:49
  SPEAKER_00: The Achilles is an energy storing tendon.
• 2:52
  SPEAKER_00: Its length and compliance allow energy to be stored during loading and returned
• 2:56
  SPEAKER_00: during propulsion,
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  SPEAKER_00: enabling the calf's complex muscle fibers to operate over smaller length changes and
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  SPEAKER_00: at slower shortening velocities.
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  SPEAKER_00: This contributes to economic locomotion and repeated force production.
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  SPEAKER_00: Consequently, Achilles capacity cannot be described by calf strength alone.
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  SPEAKER_00: The athlete not only requires sufficient plantar flexion force,
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  SPEAKER_00: but also sufficient rate of force development,
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  SPEAKER_00: tendon stiffness, elastic energy storage, and tolerance of repeated contacts.
• 3:28
  SPEAKER_00: The foot beneath the Achilles is part of the same energy storing system
• 3:32
  SPEAKER_00: and deserves attention in its own right.