All runners experienced in long-distance races, such as marathons, 10Ks and 5Ks, will tell you that speed and endurance largely depend on core strength.
If you have good core strength, the force is going down from your front arm, through your body, to your hips to the back arm. Every fiber of your body is directed to propelling it forward. But if you have weak core strength, you’re always losing some of your power, it’s like static interrupting electrical flow. However, when everything is completely stable, all of these forces are constantly getting into the right direction. That’s how you get faster.
Core strength is crucial factor in all outdoor sports activities. It doesn’t only improve speed, but also lowers the risk of injury. Therefore, make sure you work on it regularly in your training by doing workouts that focus on all planes of motion and types of muscular actions (held, rotational and linear).
There’s a large number of various exercises to choose from; planks, glute bridges, crunches, hyper-extensions, leg lifts, chinnies and so forth. You just have to do them!