To me this highlights the problem we have with elite level sport today. With so many allegations and proven stories of doping violations, cover-ups and corruption over the last 18 months just about any athlete who produces a world class performance or, makes leaps in fitness, is almost instantly suspected of using nefarious methods.
I have little doubt that there are athletes / coaches / officials / administrators who will cheat however, I also have little doubt that there are many more who would never dream of doing so.
In regards to the Great Scottish Run...there are many rumours that the course may have been a little short, indeed I believe Callum was just as surprised about his time as anyone else. If this is indeed true, that could / would explain his extraordinary performance at the race.