Last year, someone held a plank for eight hours, 15 minutes, and 15 seconds. He was a former U.S. Marine, but he could probably clock a mean marathon time if he tried—because a strong core is crucial in keeping you upright during long runs, and planks are one of the best multitasking moves for increasing core strength and stability.
“Planks are an easy way for runners to activate much of the core system without something like a crunch, which targets only a few parts,” says Samantha DuFlo, an RRCA-certified running coach and founder of Indigo Physiotherapy. They also build running-specific strength, because your back isn’t supported while you perform one, says Meredith O’Brien, a USATF-certified endurance coach, ACSM-certified personal trainer, and head coach and owner of East Coast Run Project in Virginia Beach, VA. “That makes the muscles work in the same way they’ll have to when running: stabilized in space,” she explains.
Of course, that only applies if you’re doing a plank properly. Here’s what that looks like: Your body should be in a straight line from the top of the head to the feet (regardless of whether you’re on your hands or elbows, with feet shoulder-width apart, arms or elbows directly under the shoulder at a 90 degree angle, shoulders externally rotated so elbows point straight back and not outward, belly button pulled in towards the spine, glutes squeezed, and head and neck in a neutral position.
That’s a lot to keep in mind for a static position. But when you do a plank right, it will activate the transverse abdominis (the deepest layer of abdominal muscles, which stabilizes the entire low back and core), the rectus abdominis muscle (the “six-pack abs” responsible for forward flexion of the trunk), the obliques (which help flex and rotate the trunk), as well as muscles along the spine (which help keep you upright) and the serratus anterior (which aids in stabilization).
“These muscles all play various roles in different phases of the running cycle,” explains DuFlo. A key component of running form is trunk rotation, which means your thoracic spine and rib cage should be rotating side to side, she says. The obliques help facilitate that trunk rotation. And arm swing is critical for energy efficiency; the serratus anterior adheres the scapula to the trunk, so your arm swing occurs with the shoulder girdle. “All of these muscles work together to create a biomechanically intelligent running form that allows for dynamic stability, energy efficiency, and load transfer—AKA better endurance, better strength, greater speed,” she says.
A proper plank also builds stability in muscles that support the hips, including the transverse abdominis, rectus abdominis, and (especially) the glutes, says O’Brien. “Hip stability is incredibly important for runners,” she explains. “Think of the hips like a container full of energy and power: If they get tilted forward or back because the body can’t stabilize, all of the energy falls out.” Plus, that tilt at the hip can lead to form breakdowns like overstriding and a crossover gait (where it looks like you’re running on a tightrope), she adds. “These faults can lead to injury while costing a runner efficiency.”
At the same time, holding your bodyweight up against gravity will work muscles in your upper body, including your trapezius, rhomboids, and pecs. That matters for runners, because “your arms act as a counter balance to your legs,” says O’Brien. Weakness in the upper body can also lead to imbalances that affect your speed and power, and change how your arms move, sending them across your body instead of forward. “Since we want to go forward when we run, sending energy sideways isn’t ideal,” she says.
How to Improve Your Basic Plank
Once you’ve nailed the proper plank form, challenge yourself with these slight modifications—they’ll help you really tap into all the benefits you can get from spending that time on your hands and forearms.
1. Stop praying
Clasping your hands in a forearm plank makes the exercise feel easier—but that means you’re not maxing out the benefits. “It can also promote a rounded posture instead of a stable, upright one,” says O’Brien, and that’s the opposite of what you’re going for in this position. Instead, press your palms into the floor. “That will create more shoulder engagement and stability as a bonus.”
2. Stay up
A straight arm plank is going to be more challenging, says O’Brien. But “dropping to the elbows can help you maintain proper form because it’s easier to hold,” she says. It’s a great option for someone who isn’t yet strong enough to maintain an engaged core and flat back (it also takes some of the work off of the shoulders, if that’s a problem area for you).
3. Don’t hold your breath
It’s tempting to grit your teeth as you hold the pose, but you want to inhale and exhale steadily throughout. “Breathing will help you consciously engage the transverse abdominis muscle,” says DuFlo. “If you see your belly doming or bulging outward along midline, it means you are likely not engaging this correctly or holding your breath.”
4. Plank on an unstable surface
If holding a plank for a minute or more is easy for you, place your palms, forearms, or feet on a pillow, BOSU ball, Swiss ball, or other unstable surface. “That can kick on the deeper core, the transverse abdominis, in a different way, and just add an additional challenge to your other muscles,” says DuFlo.
5. Switch it up
There are tons of ways to make a plank more challenging, in addition to targeting other muscles that will help your running form. Spider planks (bringing your knee to tap the same shoulder) and windshield wiper planks (where you extend one leg at a time out towards the hip) help with the hip rotator muscles, for example, while reverse planks activate the glutes and stretch the chest, says O’Brien. Just make sure you can maintain good form while doing these harder variations.