There are a bunch of different reasons that serious endurance athletes generally don’t have big pipes. The most obvious one is that they spend a lot of time running and pedaling and so on, and very little time pumping iron. There may also be an “interference effect,” in which endurance training directly counteracts some of the effects of strength training. And it may be that marathoners simply aren’t wired to get big: researchers have long suspected that slow-twitch muscle fibers, which are most plentiful in endurance athletes, don’t respond to training in the same way as fast-twitch fibers.
This last idea is of particular interest to people like me, who after long years of endurance training have grudgingly accepted that their long-term health would likely benefit from packing on some more muscle. I’ve included strength training in my routine pretty consistently over the past decade, but I’m in no danger of needing to buy bigger T-shirts. So I’m interested to know whether my muscular profile is ill-equipped to add mass, and if so, whether there are any particular training strategies that would work…
