I put this post in another thread (on another board) a few days ago (actually, 2 years ago now, but I wasn't here then, and I've just found it again to link elsewhere in reference to Corbs' latest knee op); which got largely ignored as the thread turned into the match thread for the All Blacks, and just moved on so quickly. I feel it's an important issue though - and one I seem to go on about every year, though never in much detail. It was initially a reply to someone else's post, so may read a little oddly out of context, though I've edited it a little to avoid this.
I thought it deserves a proper airing:
Why I don't think young front row players should play more than ~600 minutes (~10 starts / 30 benches) 1st class matches per season before their 23rd birthday.
The growth plates (AKA epiphyseal plates if you fancy heading to google) of the bones fuse around 22-23 years of age; no amount of gym work will change that; luck and normal distribution curves can, but nothing else*. This is nothing to do with size, or weigh, or muscle bulk; it's entirely due to the bones not being strong enough. This is not something you can train; it's a simple fact of life*. It's so much a fact of life, it's how forensic pathologists determine the age of death for skeletons.
*Well, ish; but not let's confuse the issue with drugs.
At the age of 22 you still have unfused bones in your knee (proximal tibia, distal femur) and shoulder (humerus head and acromion); which are the ones I'm most interested in (also iliac crest, wrist and plenty in the sacrum, but these are much less important). Spinal ossification ages are much more variable though; tending to fuse (sacrum aside) in the 20-25 age range IIRC; these are typically more stable however, once they start fusing.
Too much force through these areas before fusion causes distortion causing all sorts of problem, including debilitating arthritis before 30 years of age.
OK, some will be lucky, either fusing a year or so earlier than expected, or simply getting away with it; but for every Healey (who may yet need a wheelchair by the time he's 50) there's a Corbisiero; for every Vickery there's a Woodman, for every AJones there's a DFlatman.
Hell it's not just front rowers either, they're just the ones with the most extreme pressure coming through knees and shoulders - look at James Forrester (retired aged 27 through arthritis), or Martin Haag (needed 2 walking sticks by his mid-40s, 1 artificial knee, the other may have been done by now).
It's probably worth pointing out (again) that it's not just their playing career I'm worried about, though it's certainly an issue; I don't like dealing with patients who need knee replacements in their 30s because they or their coaches were idiots 15 years earlier. It's also not just the top class players; it's just that they're an exaggeration of this, with more training, and more force whilst playing.
To demonstrate and spot the difference: 1st X-ray is a ~20 year old; 2nd is a ~23 year old. Which do you think looks stronger / better developed?
Good summary of the ages of ossification for the long bones here:
The likes of Corbisiero*, Woodman**, Thomas*** etc are the prime examples of what I'd like to avoid.
* 2000 minutes in 3 seasons before 23rd birthday
** 1100 minutes in 1 season aged 22
*** 1000 minutes aged 19, 700 aged 20, then notably less due to the inevitable injuries
