Good points Trevor

I've always been a fairly strong bloke, quite strong shoulders, and since starting WFP and pushing myself hard on the high, heavy work, I've increased my stamina with regards to using WFP.
So to a point I understand and agree with you.
To build up resistance to lactic acid fatigue you have to keep experiencing it...try speed walking for about 400m (make sure no one is looking though cos you'll look a berk!

)
The pain in your calves is unbelievable.
Ditto the training you have to do for tug of war, your forearms feel like they are going to explode

Ever used a Concept 2 rowing machine?
Push yourself over 2000m and you have aerobic pain and anaerobic pain to deal with.
To extend your thresholds takes effort, and to do that you have to push yourself.
Unfortunately with WFP (and trad too) the range of movement is limited and highly repetitive, often, and in particular with WFP, you are extending yourself unnaturally and unevenly on many occasions.
If you are naturally strong and robust you will cope better than those who are not with the strains of the job.
Some will discover certain weaknesses in their bodies and they will not work on the areas they need to to strengthen themselves and thereby helping to protect themselves from injury.
And it isn't remotely easy to work out what it is you actually need to do to combat or correct the problem.
for instance:
It has taken 9 years for Squeaky's body to go 'twang'
rog is excessively right handed and I'll bet that this has had a major impact on the fact he is now 'damaged goods'
his body had become unbalanced, eventually, no matter who you are, your body will turn on itself and go 'twang'
But working out what you need to do to keep your body in balance (or harmony) is beyond most of us.
And so, whether a desk jockey using a keyboard all day long, or a window cleaner using a pole all day long, we'll continue to injure ourselves as our bodies break down under the strains we put it under
Don't mind me...it's a Sunday and I'm bored..so just musing away on here
Ian