Range 
≈0.83 µm^2/day

Organism 
Mouse Mus musculus 
Reference 
Rutenberg AD, Brown AI, Kreplak L. Uniform spatial distribution of collagen fibril radii within tendon implies local activation of pCcollagen at individual fibrils. Phys Biol. 2016 Aug 25 13(4):046008. doi: 10.1088/14783975/13/4/046008. p.3 right column 2nd paragraphPubMed ID27559989

Primary Source 
[3] Kalson N S, Lu Y, Taylor S H, Starborg T, Holmes D F and Kadler K E 2015 A structurebased extracellular matrix expansion mechanism of fibrous tissue growth eLife 4 e05958 doi: 10.7554/eLife.05958.PubMed ID25992598

Method 
Primary source abstract: "[Investigators] present a model for fibrous tissue growth based on 3Delectron microscopy of mouse tendon." 
Comments 
P.3 right column 2nd paragraph: "[Investigators] can now check the quasistatic approximation underlying equation (1). For it to be valid [they] need the neglected term (δρ/δt) to be much smaller in magnitude than the incorporation rate s. Using the solution equation (2) to evaluate δρ/δt, the ratio of the terms is δρ/δt/s=d(πR^2)/dt/(4πDcol)≈1.0×10^7, (8) where d(πR^2)/dt≈0.83µm^2/day is the rate of bundle area increase from birth to 6w [primary source]. [Investigators] see that the dimensionless ratio is vanishingly small, i.e. the quasistatic approximation was well justified. Fibrils and bundles grow slowly compared to diffusion timescales." 
Entered by 
Uri M 
ID 
112908 