Runners are inundated with messages about the importance of core training. And while most understand the link between weak core muscles and injuries, there's a debate about what "core" means and the best method to strengthen it.
For decades, "core" was synonymous with ab muscles. Perhaps the traditional approach to core training was a result of those runners with six-pack abs who often adorn the covers of running magazines.
As we've gotten smarter about training, we've come to realize that, while strong abdominals make for a good photo op, they aren't the most important aspect of the core for runners. The core muscles include everything from the low back to the hips. They're the muscles that keep you upright and moving forward by supporting your stride.
As a result of this misguided definition of "core," many of the supplementary exercises prescribed to runners over the years was ill-advised. For example, a recent study assessed athletes' dynamic balance before, during and after three different sessions: (1) traditional core exercises, (2) dynamic trunk stabilization exercises, and (3) no core work (control condition). The researchers found the athletes demonstrated better dynamic balance following the trunk stabilization session, which included exercises such as front planks with raised arm/leg and back bridges versus the more traditional core exercises, like sit-ups and oblique crunches.
The results of this study show that balance can be improved more readily through thoughtful and focused exercises. When one considers the fact that running is a series of hops that involves repeated single leg balancing, it makes sense that runners may respond better to a more dynamic core routine that emphasizes trunk stabilization. "Just look at the performance demands of sport," says Chris Johnson, a physical therapist and coach in Seattle, Washington. "With running, you need to balance from one leg to the next and stabilize yourself in a wobble-free manner, all while make sure you're not leaning excessively from one plane to the other."
Johnson suggests testing your balance with a simple single-leg balance test. "You can take people who are doing a lot of core strength and have them try to balance on one leg and they can't do it," he explains. "They may have an 8-pack, but the second they are vertical, they can't recruit the right muscles, demonstrating these core exercises are for naught."
For this reason, Johnson emphasizes specificity when it comes to core work. Since we are vertical when we run, it is important to focus not just on dynamic core work like planks with a raised arm and leg and bridges, but also on exercises that are done vertically to strengthen the muscles that directly support the running motion.
"I often recommend a lot of slow-motion marching exercises and motor control step-ups because runners need to be stable on each leg when they are upright and vertical," he says. "If you're concerned with longevity in the sport, you have to be able to meet the specific performance demands."