Physical therapist Emmi Aguillard, DPT, who specializes in treating and training runners, agrees. “While there are some minor strength gains that can be made from running, it’s typically not enough to move the needle in a meaningful way,” she says.
Building strength “typically involves progressively overloading your system by making the exercises progressively more challenging—usually done through increasing weight,” Dr. Sekely says. For instance, exercises that help you build strength are generally done for 2-3 sets of 6-10 reps (or fewer, if max strength is your goal!), using a weight that’s heavy enough for you to only have 1-2 reps left in the tank. Then, of course, you rest to give your muscles a breather before doing it all over again.
Workouts, like running, are considered cardio when your heart rate is elevated above resting (approximately 50-85% of your max heart rate). While the latest Physical Activity Guidelines for Americans report removed the minimum duration of time necessary for these workouts to “count” toward your weekly physical activity total, cardio workouts still typically tend to last about 30 to 60 minutes, Dr. Aguillard says.
Additionally, workouts that increase your heart rate recruit type 1 muscle fibers, Dr. Aguillard explains. These types—a.k.a. slow-twitch fibers—are responsible for endurance movements, like running for longer periods of time, per the National Academy of Sports Medicine (NASM). On the other hand, type 2 muscle fibers (a.k.a, fast-twitch) power anaerobic work, or that which taps into strength and power—yes, like lifting—which can’t be sustained for a long time, Dr. Aguillard explains.
Basically, if a workout is primarily recruiting type 1 muscle fibers, it’s an aerobic workout, Dr. Aguillard explains. And steady-state running falls squarely into that.
But can you build muscle or gain strength with other types of running?
Certain types of running—like hill repeats, strides, and intervals, for instance—can build more muscle and strength than steady-state running, according to Dr. Aguillard. “When you sprint or run uphill, your muscles must contract forcefully to overcome gravity and produce speed, which leads to microtears in your muscles,” she says. When your body repairs these microtears, that’s what causes your muscles to rebuild bigger and stronger, per the NASM.
Sprinting and hills also recruits more type 2 muscle fibers, which are primarily designed for power and explosive efforts. When you sprint, you’re hitting the ground with much more force than slower, steady-state running , and when you run uphill, your muscles (especially glutes, hamstrings, and calves) are working against resistance similar to adding weights to reps at the gym, Dr. Aguillard explains.
These “strength building” runs also share some other similarities with weight lifting, like lasting for a shorter duration and taking time to rest in between, as opposed to steady-state running. You can only sustain these more intense efforts for a shorter time since you’re tapping into your anaerobic system, where you’re using the energy stored in your muscles to power you, rather than the oxygen from the air you’re breathing, Dr. Aguillard explains.
