Most runners have strong hearts and strong legs, but they forget about a key component between the two: the core. You’ve probably heard a lot about strengthening your core for better fitness. If you aren’t sure exactly what your core is, it is the group of muscles that control and support your spine and pelvis. In other words, it’s the muscles of the stomach, back, and hips.
Think of your core as the center of your energy. A strong core will move the energy out to the other parts of your body so they function at their maximum. A weak core doesn’t transfer the energy as well, so some parts of your body will have to compensate by working harder to produce the same motion. After a while, those body parts will break down from excessive wear and tear, and injury will occur.