No, it is overworded and overthought. The reason he has back pain is because he's not used to the work. Simple as that.
could have been....but thats your opinion......I prefer to give advice that some one says oh i havnt tried that instead of i already stretch at the start of my routine but thanks....
work capacity is something you can't fix over the internet. He needs to train that movement until his body adjusts to it. It is already common knowledge that well stretched legs, hamstrings in particular, are imperative for top performance. And the rib advice is just silly.
real common knowledge that tight hamstrings causes lower back pain..... the rib advice i clearly state the conditions for a disjointed rib which can be very painful and detrimental to any one that trains but i also state thats its probly just a sore muscle.