I have never fully understood how this exactly works. These questions pertain to the long term effects of strength training only.

Basic Physiology of Hypertrophy (what is understood)

  • During muscle hypertrophy you’re tearing myofibrils, which are composed of stacked sarcomere’s.

  • This tearing causes the immune system to repair the damage. Proteins called cytokines are released to the damaged area.

  • The repair occurs as satellite cells differentiate into myocytes (muscle cells) which then fuse the torn myofibrils together which increases the diameter of the myofibril.

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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2785020/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2785020/

The Physiological Effects of Detraining (what I DO NOT understand)

Detraining (as related to long term strength training) obviously leads to loss of muscular strength and power.

  1. At a basic physiological level, how is this occurring?

  2. Are the sarcomeres (containing myosin and actin) used as fuel by your body and expelled?

  3. After myofibrils decrease in diameter since they now contain less
    contractile proteins?

Full and Partial answers are both great -- ideally with supporting research. Thanks!

  • I totally want to sit down with a cup of coffee and answer this! Great question, and if someone beats me to it so much the better!
    – Eric
    Oct 16 '17 at 17:41
  • 2
    @EricKaufman would definitely appreciate it!
    – Mike-DHSc
    Oct 16 '17 at 17:43
  • I've also been looking at this, and most of what I am finding relates to #1, and fiber type conversions + attendant muscle changes. (Such as the reduction in neovascularization, etc). I am not finding anything at the moment on the sarcomeres and myofibril effects. Interestingly, I did find some suggestions that fiber angles change which could also account for some of the attendant loss of strength.
    – JohnP
    Oct 16 '17 at 19:35
  • "Detraining (as related to long term strength training) obviously leads to loss of muscular strength and power." Yes it does. Your body adapts to what you need. Assume you deadlift 500lb and then stopped training for 3 months. Since your muscles and nervous system have not been forced to do a work, their performance deteriorates. But keep in mind that when you return training, after a few months you would be able to lift 500 lb again thanks to muscle memory.
    – PIC16F84A
    Oct 17 '17 at 21:51
  • 2
    @Eric 'bout time for that cup of coffee, wouldn't you say? I'm very interested in reading an answer to this!
    – Cullub
    Jul 26 '19 at 18:11

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