Lately we’ve been addressing a common fear among runners that lifting will make them “bulky.” (Yes, I’m still on this subject because I think it’s THAT important.) And to be honest, there is some legitimacy to that fear. But let me explain.
To be clear, I don’t subscribe to the belief that so-called “bulk” is bad. It’s just muscle, folks. And often, it’s much needed!
Yet many runners are quick to throw the baby out with the bath water, thinking that lifting weights will automatically add significant muscle mass unless they lift #5 for an ungodly number of reps.
You may protest, “but I’ve tried it, and I know I put on too much muscle when I lift heavier.” While we might need to have a chat about what is considered “too much” muscle, it may just be the way your program is designed.
For the average gym-goer, the most common lifting format is generally aimed at bodybuilding, meaning it is specifically designed to increase muscle mass.
For example, if you’re lifting moderate weights for 3-5 sets of 8-12 reps, lifting to fatigue or failure, expecting to feel the burn and get a pump, then yes, the main result you’ll see (after weeks, months, and YEARS of consistency) is increased muscle mass.
There is NOTHING wrong with lifting that way. You can bodybuild and be a kick ass runner.
But, if you’re avoiding strength training specifically because you’re worried about bulk, this is important: increased muscle mass is only one of MANY possible beneficial adaptations to strength training depending on the structure of your sets, reps, and loads.
Instead, think heavier loads for 3-5 reps per set for 18-24 total reps per movement. This structure mainly improves relative strength, or the ability to produce more force as a result of improved motor recruitment and synchronization rather than relying on increased mass.
Training your muscles to coordinate and fire quickly leads to better running economy, better form, and better performance.