First of all, I love his running technique.
I've seen this video over and over:
It is normal to have a few asymmetrical moves, but he seems to run with the right arm more tight than the left arm. This creates a slight unbalance.
What injury did he had in 2011-2013?
Second, I was reading this old blog post:
http://www.runningwritings.com/2012/06/elite-marathoning-with-renato-canova.html
The author said somewhere that a possible cause for Mosop's injury from 2011 is the large variation of distances from the training cycle.
The coefficient of variation of distances in his training cycle was around 35%, while intensive was 22%.
Mo Farah has a 19% coefficient of variation of distances in his training cycle, with 10% intensive workouts. He also has moderate workouts which could count. He didn't had injuries.
Jeff Gaudette had a 10% coefficient of variation of distances in his training cycle, with 11% intensive workouts. He didn't had injuries either.
It makes me believe that the coefficient of variation of distances is correlated with both performance and risk injuries.
To compare, a training plan which has a rest day and a very long run included, has above 80-100% coefficient of variation of distances.
So, which is most likely to have caused Mosop's injuries?
A possible slight unbalance in running form, the distance variation in the training plan, or something else?