Tendon Recovery · Load It, Don't Just Rest It

肌腱修复 · 不是多休息, 是会负荷

Place · Level 3 · Recovery

肌腱慢半拍的真相 · -itis是个误称, 慢性肌腱痛是失败的修复不是炎症 · 机械负荷才是修复的开关 (mechanotransduction) · 渐进、离心、重慢负荷胜过休息 · 胶原 + 维 C 时机的诚实版本 · 类固醇注射的长期代价

Connected to · 4

cofactor · 3

Exercise as medicine
Tendon and articular cartilage are both avascular tissue, fed by load and repaired by load. Resting them is not protection but degeneration — the signal that triggers repair is, counter-intuitively, the loading itself.
Vitamin C
Vitamin C is an obligatory cofactor for collagen synthesis: prolyl and lysyl hydroxylase both depend on it, without it hydroxyproline is not made and the triple helix will not hold. Scurvy — wounds reopening, connective tissue failing — runs down exactly this path.
Protein
Collagen synthesis needs an adequate amino-acid supply (glycine and proline especially), and that comes first from total daily protein, not from a special powder.

regulates · 1

Training injuries
Resting a tendon does not repair it: collagen synthesis falls and stiffness degrades. This is why acute-injury consensus moved from strict RICE immobilisation to early controlled loading.

Why tendons heal slowly · structure is destiny

Stop 1/6

为什么肌腱好得慢 · 结构决定命运

A pulled muscle heals in two or three weeks; a 'tennis elbow' or an aching Achilles can drag on for months, sometimes a year. That is not because you are slacking — it is because tendon, as a tissue, is structurally slow. Get this and every later 'why rest alone won't fix it' makes sense.

What tendon is made of

The bulk is dense type-I collagen, laid down in parallel bundles built to transmit muscle force to bone — one of the body's highest tensile-strength connective tissuesIts cells (tenocytes) sit sparsely in the collagen matrix — few in number, low in metabolismVery poor blood supply (relative to muscle): tendon is a low-vascular, low-oxygen, low-metabolic-rate tissue — the first reason it heals slowly
How slow: the carbon-14 nuclear-bomb-pulse experiment (Heinemeier et al. 2013)

A beautiful natural experiment: the 1955-1963 nuclear tests spiked atmospheric ¹⁴C, effectively 'time-stamping' people born or growing in those yearsThey measured ¹⁴C in the core of adult Achilles tendons. The result was striking: it matched the atmospheric level from before that person turned 17 (the height-growth years)Meaning: the collagen in the tendon core is laid down during growth and barely renewed in adulthood — in sharp contrast to muscle, which turns over continuouslyThis explains at the molecular level why tendon 'heals slowly once injured and gets more brittle with age'
The framing in one line: tendon does not 'fail to heal' — it renews extremely slowly. Precisely because it is slow, it is fussy about *how* you stimulate it to repair — and as the next stop shows, that stimulus surprises most people: not rest, but load.

(Articular cartilage is a similar avascular tissue that is 'fed and repaired by load'; for that thread you can dive 到 exercise-as-medicine and its exercise-tissue-adaptation section.)

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Educational content, not medical advice — consult a clinician.

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