I often hear the claim that running promotes muscle loss. To what extent is this true? If a person is a triathlete don't they need both cardio and muscle? Does it matter what distance is run and the speed?
I first red such a claim on this article, though it clearly is not scientific.
And while the idea of masculinity varies somewhat from era to era and from one region of the world to another, masculinity is usually associated with superior strength, muscularity, speed, and power. The human body, as it turns out, isn't a very good multi-tasker when it comes to "S.A.I.D." (specific adaptation to imposed demand). It prefers to be either big and strong, or small and weak, (albeit with good endurance). True, some guys can manage to have it both ways, but if you find it challenging to gain muscle or strength, you're not one of them.
This article seems to second it but also isn't scientific.